/srv/irclogs.ubuntu.com/2012/12/12/#ubuntu-arm.txt

sfeolequince: hold the side power button down and it should reset00:15
sfeolequince: thats a known issue (onscreen keyboard becoming unresponsive)00:16
quincesfeole: I wasn't able to reset it by holding the power button down (for about 5 seconds -- perhaps not long enough?)00:50
lilsteviequince, what do you mean by "(but not using fastboot -- why?)"00:52
quincelilstevie: I tried running sudo fastboot reboot, and that printed "< waiting for device >" but had not other obvious effect00:54
quince*no00:55
lilsteviequince, but everything else you typed would suggest you were in userland00:55
sfeolequince: yea not long enough, 15 seconds will reboot it.00:55
quinceuserland?  not sure what you're referring to in this context00:56
quincesfeole: ok00:56
lilsteviequince, you were running ubuntu00:56
lilsteviefrom what it sounds like00:57
lilstevieor android00:57
quinceon which device?00:57
quinceboth my desktop and the nexus 7 were running ubuntu00:57
lilstevieyeah I mean on your nexus 700:57
lilsteviefastboot only works in fastboot mode00:57
quinceI was running fastboot on the desktop00:57
lilsteviewhich is in bootloader00:57
lilstevieok, let me simplify this00:58
quinceok00:58
lilstevieI will differentiate both, fastboot-util for the thing you run on your computer00:58
lilsteviefastboot for on device00:58
quincethink you alrready explained...00:58
lilstevieto issue commands from fastboot-util your device has to be in fastboot mode00:59
lilsteviewhen you are booted into an OS you are not in this mode00:59
quinceright -- was clear from "only works in fastboot mode" :-)00:59
lilstevie:)01:00
rasterm0002:20
=== zz_chihchun is now known as chihchun
sbaughIs Ubuntu on the Nexus 7 at a point where it's usable without an external keyboard/mouse?05:40
achiangdefine "usable" ? :)05:43
sbaughachiang: Good point :) If I just wanted to do some reading and surf the web and do some tinkering, would I be able to spend a good couple hours without critical bugs?05:49
achiangsbaugh: you'll probably still hit the "button1 stuck" bug, which is frustrating05:50
achiangbut anecdotally, if you don't exercise the unity elements too quickly (like opening/closing the dash too quickly or opening the indicators) you'll be ok for a while05:50
sbaughachiang:  https://bugs.launchpad.net/ubuntu-nexus7/+bug/1068994 is this it?05:50
ubot2`Launchpad bug 1068994 in ubuntu-nexus7 "button1 gets stuck after a while" [Critical,Confirmed]05:50
achiangsbaugh: yeah, basically it stops responding to touch input :-/05:51
achiangit's deep in the guts of X so hard to figure out05:51
sbaughachiang: Is that the only major bug I might run into?05:53
achiangwell, there are lots of others, but i don't think they are show stoppers, as bad as button1 stuck05:53
sbaughThen, it is time to flash!05:54
achianggood luck. :)05:55
sbaughHey, heh, I tried flashing but I'm getting a password propmt which rejects my password even though I'm sure I'm entering it right06:23
sbaughFor permission to run ubuntu-nexus-installer06:23
achiangshould be your typical sudo password06:28
achiangdo you have sudo perms?06:28
sbaughYes06:31
sbaugheven changing user to root and running it, it still fails06:32
sbaughearth : Dec 12 01:11:30 : root : 3 incorrect password attempts ; TTY=pts/3 ; PWD=/home/spencer/Downloads/UbuntuNexus7 ; USER=root ; COMMAND=/usr/bin/[ 1 ]06:35
sbaughIs the mail sent to root to notify of the attempt06:35
achianginteresting, this is not my area of expertise06:37
Etherninsbaugh, dude use fastboot06:37
achiangvanhoof will wake up in a few hours. :)06:37
Etherninsbaugh, fastboot is way better and you can actually see what's going on06:38
Etherninjust download the latest raring image off the wiki06:38
sbaughEthernin: Do you mean do it manually? Fastboot seems to detect my device but it isn't letting me do anything.. mhm06:38
Etherninit should06:38
Etherninu r root?06:38
sbaughby anything, I mean restart06:38
sbaughah06:38
sbaughno06:38
sbaughi wasn't root when i executed that command06:38
Etherninok 1 - be root06:38
Ethernin2 - is your nexus in fastboot mode?>06:38
Ethernin?06:38
sbaughokay, oyes06:38
Ethernink06:38
Etherninyou should be able to do -06:39
Etherninfastboot erase boot06:39
Etherninfastboot erase userdata06:39
Etherninfastboot flash boot raring*.bootimg06:39
Etherninfastboot flash userdata raring*.img06:39
Etherninfastboot reboot06:39
sbaughoh, haha06:40
sbaughhow odd06:40
sbaughi did fastboot reboot06:40
sbaughit seems it's already been flashed06:40
Etherninis your bootloader unlocked?06:40
sbaughi must have gotten through the first time and not noticed06:40
sbaughgreat, it's booting06:43
Etherninsaweeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeet06:44
Ethernin;-)06:44
Etherninwhich nexus do u have?06:44
Ethernin16 or 32?06:44
Etherningb?06:44
sbaugh1606:44
Etherninword yeah i have one of those06:45
sbaughhanging for quite a while on wireless06:49
sbaughin the first-start system config06:49
sbaughwould it hurt to just power cycle?06:49
Etherninomg06:55
Etherninyeah06:55
Ethernini had to deal with that fucking thing like 10 times06:55
Ethernindid u install the latest raring image?06:55
sbaughyes06:56
sbaughand now i'm06:56
Etherninthe initial menu is SUPER buggy when it comes to connecting to the wifi06:56
Ethernini usually skip it and connect after06:56
sbaughstuck at the account setup06:56
sbaughcan't seem to enter any text06:56
Etherninyeah, u may want to plugin a keybaord06:56
Etherninyeah keep tapping06:56
Etherninanother bug for sure06:56
sbaughonboard is up06:56
Etherninjust keep tapping06:56
sbaughokay06:57
Etherninthe input fields06:57
sbaughok06:57
Etherninsuper buggy but u should be able to06:57
Ethernini had the same thing happen like 10 times06:57
sbaughis there a way at this point to connect remotely06:57
sbaughand do this?06:57
Etherninyeah attach a external usb keyboard via OTG cable06:57
Etherninand tap tap tap away06:57
sbaughno, i mean, ssh or vnc or something06:57
Etherninthey really need to fix the initial menu, and stop a bunch of services like cups06:58
Etherninunity is super slow too06:58
Ethernini find xfce and lxde to be the best06:58
Etherningnome classic is pretty good too06:58
Etherninyeah but u have to install them first06:58
sbaughi was planning on lxde06:58
sbaughoh06:58
sbaughdrat06:58
Etherninyeah lxde is very nice06:58
sbaughyou're right06:58
Ethernin;-)06:58
sbaughubuntu doesn't ship with an ssh server, right?06:58
Etherninapt-get install openssh-server06:58
Etherninonce yer in06:58
Ethernini knwo the initial menu is really buggy....06:59
sbaughisn't there some serial connection thing06:59
sbaughyes, I see on here: https://wiki.ubuntu.com/Nexus7/UsingTheDevice07:02
sbaughoh god07:03
sbaughwhat is the default accout name and password? ubuntu/ubuntu doesn't seem to work?07:03
infinitysbaugh: There is no default account.07:05
infinitysbaugh: First boot after flashing it should give you an installerish deal that prompts to create a user.07:05
sbaughinfinity: I'm having trouble with that so I thought i'd bypass it with the serial connection.07:06
infinityWell, see above.  There's no default user.07:06
Ethernininfinity, the initial menu config after install is SUPER buggy, often u have to tap many times to actually input text into the user/pass fields, and sometimes it doesnt even work07:07
sbaughThere's no way I can get on the device without going through this setup? :(07:07
Ethernininfinity, just an FYI if u didn't already know07:07
sbaughBecause like Ethernin said it's barely functional07:07
infinityxnox: You know anything about the current uniquity-versus-input issues?07:08
sbaughEthernin: I should be tapping the field itself, correct? And when will I know I am able to input text?07:08
Etherninsbaugh, yeah that's what worked for me07:09
sbaugh(as opposed to the keyboard)07:09
Etherninyeah u will have to show onboard too if it isn't07:09
infinitysbaugh: If you can boot with an arbitrary commandline, you could always boot with init=/bin/sh and set stuff up via serial.  I'm on my way to bed, though, so can't be particularly helpful on that score.07:10
infinity(Obviously, us fixing whatever's currently plaguing the installer is the better option here)07:10
Ethernininfinity, thank you!07:11
sbaughinfinity, I would ask how I would go about booting in such a way, but Ethernin, maybe you can explain?07:12
Etherninif it really doesn't work, try rebooting, if that doesn't work u can always reflash07:13
Etherninbut really u should get an OTG usb cable07:13
Etherninso u can plug in a usb keyboard ect07:13
Etherninthat's always my backup at this point ;-)07:13
sbaughyes, I should, but I don't have one right at the moment :)07:13
sbaughWould I need to reflash to change init or etc.07:14
Etherninhonestly I would try reflashing - it's the simplest quickest option07:15
sbaughOkay, so how would I flash differently this time around?07:16
Etherninno07:17
Etherninsame07:17
Etherninjust follow the wiki, erase, and flash07:18
Etherninand reboot07:18
Etherninbefore that u could try rebooting the device07:18
Etherninby holding the power button07:18
Etherninand maybe it will prompt u with the menu again07:18
Ethernintry that before reflashing07:18
sbaughalso I seem to have accidentally rotated the screen, is the hotkey super-something?07:19
Etherninum....not sure about that one!07:19
sbaughI'm not sure I just want to reflash and hope. Isn't there anything more direct I could do?07:25
kulvesbaugh: http://ruedigergad.com/2012/12/09/nexus-7-easily-flashaccess-entire-userdata-partition/07:26
kulveyou can mount the partition over usb to your PC and add root passwd there. I think then you can log in as root07:26
sbaughkulve: Do you know how I would do this more specifically? I'm having trouble telnetting in (I'm also unsure how I would mount the user partition)07:36
kulvewhat parts have you done now? Did you already boot with the moslo images?07:38
sbaughYes07:38
sbaughBut that's as far as I've gotten07:38
gurgalofit should come up as a usb massstorage device...07:39
kulvenow you should already see the big partition in your Linux box. "dmesg" should tell you the /dev/sdX device for it?07:39
sbaughah, okay, it's appeared07:42
kulvesbaugh: use "mkpasswd" to create a password hash for you and add it to etc/shadow file on the mounted file system07:43
kulveto my understanding that's enough to enable the root user07:44
sbaughshadow should currently be blank?07:45
sbaughah07:46
sbaughwhoops07:46
sbaughnevermind, ignore me07:46
sbaughso I should just put the hash after root? Or make a new line for a new user?07:47
kulvechange it for root07:48
kulveadding a new user would need editing passwd and group files as well as adding a home directory. So it's easier to enable root user :)07:49
kulveif you get that working, you can then adduser in a live system (although doing that graphically might be better idea in ubuntu)07:50
sbaughkulve, and i'm replacing the * in root:*:151414:etc.?07:50
kulveyes07:52
kulveI hope I remember this correctly as I haven't done that many times..07:52
kulvesbaugh: and do make sure you edit the device's file system and not your real one ;)07:53
sbaughgood advice :)07:53
kulveI often cd to the mount point and then vi /etc/foobar instead of vi etc/foobar ..07:54
dholbachgood morning07:55
sbaughkulve: as before it is immediately saying "Login incorrect" if I enter root as my login (not letting me get to password)07:57
sbaughDo I also need to enable logging in as root, perhaps?07:58
kulveHow are you logging in as I assume you don't have wifi up?07:58
sbaughThe serial connection mentioned here https://wiki.ubuntu.com/Nexus7/UsingTheDevice07:59
kulveI think you need to make sure ttyACM0 is in /etc/securetty to allow root login through ttyACM008:00
sbaughwell then08:00
kulveit might not be there by default08:00
sbaughgreat!08:08
sbaughawesome, thanks kulve08:08
kulvenp :)08:08
kulvethat moslo stuff is quite neat, if you want copy something big over there08:08
sbaughnothing I really need08:09
sbaughwill the installation wizard still come up if there's a user set up?08:09
kulveno idea08:10
cortexA9hello08:35
sbaughexcellentttttttttt08:37
=== buildslayer is now known as shadeslayer
cortexA9testing 12.10 to 13.04 on nexus 7 :)09:05
victorpogra_, ping09:12
sbaughOkay, the issues with the first-run configuration wizard seem to be issues with Unity; I managed to run it under LXDE and it worked fine.09:19
sbaugh(Or possibly just the window managers)09:19
xnoxinfinity: on nexus7 with ubiquity on compiz, ogra reported onboard "fighting" for the screen estate with ubiquity somehow. But I am yet to look into that.09:22
cortexA9mmmm09:29
cortexA9preparing to replace bluez..09:30
cortexA9very strange09:30
cortexA9it takes few mins09:30
cortexA9i try to upgrade to 13.0409:31
cortexA9from 12.1009:31
=== cortexA9_y is now known as cortexA9
cortexA9i have problem with bluez09:55
cortexA9can i remove it ?09:55
smartboyhwcortexA9, don't they recommend that you NOT upgrade but instead to refresh the image?09:56
smartboyhwcortexA9, anyway you can install the 13.04 image using the instructions here: https://wiki.ubuntu.com/Nexus7/Installation09:56
cortexA9smartboyhw: i tried09:56
cortexA9but with multirom doesn't work09:57
cortexA9and now i try to upgrade09:57
cortexA9lol10:03
cortexA9i remove it10:03
cortexA9and now seems work10:03
cortexA9:)10:03
smartboyhwcortexA9, :D10:03
cortexA9i don't care bluetooth :P10:04
cortexA9no.. doesn't work :P10:32
smartboyhw:P10:35
cortexA9wait10:36
cortexA9try another method10:36
cortexA9lol10:38
cortexA9now i don't have wifi :(10:38
cortexA9there is a problem with wifi on nexus 7 ?11:25
cortexA9because i can't see that after upgrading the packages.11:25
LaneyCan somebody try running rhythmbox with gstreamer1.0-plugins-ugly on their nexus 7 please?11:38
LaneySee if it crashes like mine does ...11:38
Laneywith ... *installed*, that is11:38
Laneyhttp://paste.debian.net/215757/11:41
kulvelooks like there's some armv4 assembly that's not supported on the nexus 7's armv7 anymore?11:52
kulvewell, the function is still _armv7_tick..11:53
suihkulokkikulve: the code might be catching sigill to figure out what instructions are supported11:53
Laneyyeah might be likely; if I continue I get to the real segfault11:55
suihkulokki..and that is indeed what is happening, looking at armcap.c11:56
LaneyProgram received signal SIGSEGV, Segmentation fault.11:56
Laney[Switching to Thread 0x4d5e9280 (LWP 3168)]11:56
Laney0x4ab93760 in mad_layer_III () from /usr/lib/arm-linux-gnueabihf/libmad.so.011:56
suihkulokkikulve: catching SIGILL is btw one common way detect (un)supported instructions11:57
kulveok11:57
Laneygdb > handle sigill pass nostop11:57
suihkulokkiLaney: aye11:57
Laneyhttps://bugs.launchpad.net/ubuntu/+source/libmad/+bug/98984612:01
ubot2`Launchpad bug 989846 in libmad (Ubuntu) "libmad causes mpd to seg fault on update" [Undecided,Confirmed]12:01
dholbachcortexA9, it works for me12:13
dholbachLaney, yes, it crashes for me too12:19
dholbachstill surprised I don't get anything in /var/crash12:20
Laneynot surprised :-)12:20
LaneyI don't get any apport goodness either12:20
* Laney will have a poke at it now - building libmad debug package atm12:20
Laneyno ddeb for some reason12:20
dholbachjanimo, do you know if apport should run on the nexus7?12:21
dholbach(like catching crashes)12:22
cortexA9dholbach: on 13.04 ?12:25
dholbachcortexA9, yes12:25
cortexA9oh nice12:25
cortexA9how you do that ?12:25
dholbachcortexA9, I tried both an upgrade from 12.10 and a fresh installation - wifi worked for me in both cases12:25
cortexA9you have multirom too ?12:25
dholbachcortexA9, what does "dpkg -l | grep linux-firmware" give you?12:26
dholbachI'm afraid I don't know what multirom means12:26
cortexA9it's a system for nexus 712:26
cortexA9for dual boot12:26
cortexA9ubuntu and roms12:26
dholbachcortexA9, ah, no - no dualboot12:27
cortexA9dholbach: linux-firmware 1.9812:29
cortexA9firmware for linux kernel drivers12:29
dholbachyou might be missing this one12:30
dholbachlinux-firmware-nexus7                     0.212:30
dholbachbest to download it here https://launchpad.net/ubuntu/+source/linux-firmware-nexus7/0.2/+build/3986720/+files/linux-firmware-nexus7_0.2_all.deb and copy it over with a usb-stick or something12:30
dholbachit's a problem which has been fixed since a couple of days already - it was a missing recommends of another package12:31
cortexA9how can i copy it ?12:31
cortexA9mmm12:31
cortexA9i can't with a stick..12:31
cortexA9i have no connection12:31
dholbachhttps://wiki.ubuntu.com/Nexus7/UsingTheDevice#Attaching_a_USB_Device_to_the_Nexus_712:33
=== chihchun is now known as zz_chihchun
diwicdholbach, I believe apport is not yet working on ARM but that pitti is working on it12:35
dholbachhm ok12:35
cortexA9mmm12:37
cortexA9with usb cable not working i think right ?12:45
dholbachhm?12:45
cortexA9yes i mean12:45
cortexA9with the cable12:46
cortexA9attach on pc12:46
dholbachput the .deb file on the usb stick on your PC and then connect it to the usb cable to the nexus712:46
cortexA9i can't see the nexus 712:47
dholbachI used a usb mass storage device (usb stick, memory stick), which I first connected to my laptop and then to the nexus712:50
cortexA9oh nice12:51
cortexA9but you have a special cable ?12:51
dholbachyes - it's mentioned in https://wiki.ubuntu.com/Nexus7/UsingTheDevice#Attaching_a_USB_Device_to_the_Nexus_712:51
=== zz_chihchun is now known as chihchun
cortexA9what about serial debug shell ?12:54
dholbachI have no experience with it12:54
janimodholbach, apport should run on the nexus. I know it was disabled by default on the 12.10 images though12:56
janimonot sure about raring12:56
dholbachjanimo, /etc/default/apport looks like it's enabled12:56
dholbachand pitti told me to look this up:12:57
dholbachdaniel@nexus7:~$ cat /proc/sys/kernel/core_pattern12:57
dholbach|/usr/share/apport/apport %p %s %c12:57
dholbachdaniel@nexus7:~$12:57
janimodholbach, are things crashing and apport not running?12:57
dholbachwhich supposedly indicates that it's up and running12:57
janimoI don't know much about this side, never saw the apport dialog on nexus7 either now that i think about it12:57
dholbachjanimo, pitti is reflashing his nexus and looking into it12:57
janimoalthough I saw recently some apport/arm related changes from pitti12:57
dholbachyes, apport seems to be able to retrace crashes from foreign architectures, so LP would know what to do with crashes12:58
janimobut I think it was disabled very early in the nexus project as it probably came up too often12:58
dholbachbut errors.u.c needs an update still12:58
dholbachI can pass on any more information I get13:00
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=== zz_chihchun is now known as chihchun
=== chihchun is now known as zz_chihchun
dholbachjanimo,14:10
dholbach<jibel> looks like core dump is disabled on the nexus714:10
dholbach I've set core_pattern to /tmp/core.%e.%p.%h.%t14:10
dholbach then as a normal user ulimit -c unlimited14:10
dholbach and  sh -c 'kill -SEGV $$'14:10
dholbach that should produce a file /tmp/core.sh.*14:10
dholbach and there is nothing, while it works on a my desktop14:10
dholbachnot sure though what they're going to do about it14:11
janimodholbach, I don't see anything in the ubuntu-defaults-nexus7 package that would disable core14:15
janimoI had no idea we do that either14:15
janimojust about apport that was off in 12.1014:15
erupterhi there14:24
erupteri'm having some weird problems with ubuntu on a pandaboard14:28
erupteranybody wanting to help?14:29
erupteris this the right channel to seek help installing ubuntu-desktop on a pandaboard? it's the 10th time I have to start again after the board fails to boot14:33
highvoltageerupter: if you'd like help, it's better to be specific. you have to provide details on what you've done and what actually went wrong.14:33
eruptersimple14:54
erupterfollow these steps14:55
erupterhttps://groups.google.com/forum/#!topic/pandaboard/7DLabw7amBg14:55
erupterwhenever the board finish the ubuntu-omap-extras installation and I reboot, it fails to boot again14:56
erupterno error message14:56
erupterit starts booting, getting up to "uncompressing linux kernel, booting"14:56
erupterand then restarts and bootloops14:56
eruptereither this, or the unity environment fails to load (no launcher) after the dist-upgrade14:57
erupterthe only way that works is the clean 12.04 preinstalled image14:58
erupter(without hardware acceleration it's quite slow)14:58
=== Ursinha-afk is now known as Ursinha
=== nemik_ is now known as nemik
Laneyapparently core dumps are disabled in the kernel16:33
dholbachLaney, do you know if it's easily fixable?16:34
Laneyi don't know what the limitations are16:35
Laneylet's rock and roll over to #ubuntu-kernel16:36
Laneywell, I found out how to enable it in the kernel I think17:12
Laneylet me try it and see what happens17:12
Laneyhttp://www.rt-embedded.com/blog/archives/enabling-core-dumps-in-embedded-systems/17:12
achiangLaney: that's a kernel thing? i thought it was userspace (ulimit) ?17:21
Laneyachiang: If I'm getting this correctly it needs to be enabled in the kernel in the first place17:25
Laneythe nexus 7 kernels indeed don't have it compared to the stock ones which do17:25
achiangLaney: ah, ok. nice find. that should probably be a bug17:25
Laneyi'm checking it out now17:25
Laneythen we can do a fix however kernel fixes get done17:25
sbaughmy battery seems to be taking forever to charge18:00
kulvecharging with what?18:01
sbaughwell, I'm not charging with the bundled nexus 7 charger and cord, but with android it still charged18:02
sbaughand, I am assuming it isn't charging from the little battery charge screen when it's off18:03
sbaughBut when I'm in ubuntu I get conflicting messages about whether it's charged18:03
Laneyachiang: OK that appears to work18:11
LaneyI'm EODing now so if you want to then CONFIG_ELF_CORE=y needs to be set in the kernel18:11
Laneyotherwise I'll follow it up first thing tomorrow18:11
Laneygot a whoopsie popup and everything18:11
tassadar_heh, /proc/last_kmsg survises device shutdown, and kexec-hardboot data too18:30
tassadar_well, sort of18:30
=== yofel_ is now known as yofel
[mbm]tassadar_: guess nobody is clearing the ram19:05
[mbm]I know some of that was inte tional from the ramconsole patches19:05
sbaughthere was one really good approach to mouse input I saw in an Android VNC client, it treated the touch screen as a touchpad and left and right as regions, would it be "Write a driver" difficult or "Install a driver" difficult to do this with Ubuntu on the N7?19:06
[mbm]sbaugh: I've been saying the exact same thing19:07
AndreasWatchHi, I'm want to add ubuntu-support to an other tegra3 tablet (lenova A2109) and want to know what are the differences between the N7 android- and linux kernel19:07
[mbm]sbaugh: scummvm is another go0d example of it19:07
sbaugh[mbm]: What does scummvm do with it?19:09
sbaugh[mbm]: And, if you've been saying the same thing, do you have anything that might enable such a feature?19:09
[mbm]sbaugh: scummvm on android uses a relative movement, treating the surface as a laptop touchpad19:10
sbaughoh, ok19:10
[mbm]sbaugh: doubt anyone has actually had time to lok into it; I certainly haven't19:10
tassadar_[mbm]: yeah, I always thought that it will loose data soon after power-down, and it was shut down for like 5-10s19:39
tassadar_there was even enough data to cause kexec-hardboot patch to try run kernel from RAM, but it failed19:39
[mbm]tassadar_: have you ever seen what happens when the video driver crashes and the lcd goes cloudy and eventually turns white?19:42
[mbm]what's really happening is a slow discharge; very similar to what happens with ram19:42
[mbm]and actually the colder the chips are the slower the discharge19:43
[mbm]there was a research paper written up at one point talking about how you could take a laptop, power it down, use an upsideown can of duster to freeze the ram chips and then put them in another machine and search the ram for encryption keys19:44
tassadar_yeah, I think I saw something like that19:44
tassadar_well, I suppose I'll need a bit more knowledge about how the RAM chips19:45
tassadar_work19:45
[mbm]also I belive there's an open bug on the nexus7 ubuntu port talkign about how the framebufer isn't erased and will show part of the old desktop when x starts19:46
tassadar_yeah, same thing happens when you reboot to android from recovery19:46
tassadar_and because android does not use framebuffer anymore, last frame from the recovery just stays there19:46
[mbm]well, the basic concept of ram is simple, it's a capacitor that holds a value but will slowly discharge, so there's a refresh where the os will reach the current value and then write out the same value19:47
[mbm]s/reach/read/19:47
tassadar_hmmm, there is something I'd like to know - how does the NAND chips do it, that they will keep the data even without power?19:49
tassadar_well, wiki says that it is very similiar to mosfet, but can keep it's state even without power from outside, other then that, it's way to complex)19:58
tassadar_but I guess the proffesors at college will try to teach me how that all works in a few years, so for now it's okay)19:59
[mbm]flash is a bit more cokplicated; uses nand or nor gates to build latches20:02
=== Quintasan_ is now known as Quintasan
[mbm]bank erase command will set everything to 0xff and then writes will set tue 0 bits20:03
tassadar_hmm, that is why "empty" memory on ATmega controllers is "0xFF"20:04
[mbm]the annoyance being that once a byte has a 0 it can't be changed back to a 1 without eraseing tje entire bank20:04
[mbm]yep20:04
[mbm]nand chips allow for higher capacity than nor chips but are harder to interface20:05
[mbm]so often times bootup is done using nor chips20:06
[mbm]flash is also a few orders of magnitude slower than ram20:08
[mbm]should point out that on flash, a bank or page is often 256k or higher20:13
tassadar_that is really lot Oo20:13
tassadar_no wonder USB drives sux at small writes20:13
[mbm]that's why SSDs have a TRIM command20:13
[mbm]trim basically means ignore the old contents and just write the new value20:15
[mbm]so if the pages are 256k and you only want to write 4k, without trim you'd be reading all 256k into ram, erasing and then writing 4k along with the remainder 0f the original 256k20:16
[mbm]trim lets you short circuit the process and just 0verwite the full 256k with the new 4k data20:18
tassadar_when is it called, like is it instead of "delete" command, or during the write operation..?20:19
[mbm]it means the write command doesn't need to preserve the old data if a write doesn't end on a boundary20:20
[mbm]early ssds didn't support trim, so the init9al write was fast, but as the drive filled it couldn't simply write the data, it had to do a read, modify, write20:21
[mbm]so it slowed down over time because it didn't know the os didn't care about the old data20:22
tassadar_just to be clear - one block == one file?20:23
[mbm]not quite20:23
tassadar_I mean, if you have lot of small files, eventually you would have to put more of them into one flash block, which means you have to read it in order not to lose the other file20:24
[mbm]suppose you had a 16M flash chip, it's probably arranged into blocks of 64k or 128k20:25
* tassadar_ has 16M flash chip20:25
[mbm]as you get 9nto larger capacities the sizes go up20:25
[mbm]under linux, the mtd driver is used when dealing with nand or nor20:26
[mbm]and if you look at /proc/mtd you'll see an erasesize20:26
tassadar_yeah, it's like that on my LG P50020:27
[mbm]that's showing you how big the blocks/pages are20:27
tassadar_it has 0x00020000, which is..20:27
tassadar_g << 0002000020:27
tassadar_oh, wait, wrong channel, there is no geordi here)20:28
tassadar_128k20:28
[mbm]flash is rated in terms of how often you can erase and rewrite it before the silicon falls apart20:29
[mbm]which is on the order of 100,000 - 1,000,000 cycles20:29
tassadar_wiki says that when MLC chips are used (like in most android devices?), it is much less - around 1-10k20:30
tassadar_which scares me a bit20:31
[mbm]when you deal with flash chips hidden behind controllers like sd cards there is a certain amount of reserved space20:31
[mbm]and bad pages get automatically remapped20:31
[mbm]when dealing directly with the flash there are special filesystems like jffs2 and yaffs2 which try to distribute the wear20:32
[mbm]if you were to try to use ext3 directly you'd probably have some files which almost never change and some files which are constantly changing20:34
[mbm]which results in uneven wear, the areas with tue constant files would have only used a few cycles while the remainder of the filesystem was constantly using up cycles20:35
[mbm]one of the stupidest things you can do is wget a file directly to a flash filesystem20:36
[mbm]which will go slow because it has to constantly update the flash with the new file size and data20:37
[mbm]works much better to download to ram and then once downloaded, write the whole thing to flash once20:37
tassadar_[mbm]: okay, thanks for the explanation, I feel like It gave me more than the last month and a half in school :) I have to get some sleep now, gn21:00
EtherninHey u guys, can I ask how many of you have ubuntu installed on a Nexus7?21:21
Etherninjust curious...for those who are running ubuntu on a Nexus7 - what desktop environment has worked the best for you?21:23
EtherninI'm finding even tweaking unity it is practically unusable21:23
=== awafaa_ is now known as awafaa

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