Re: On XO-1.5 with 11.3.0/11.3.1 -- hang during shutdown?
On 21 June 2012 16:14, James Cameron qu...@laptop.org wrote: On Thu, Jun 21, 2012 at 02:37:35PM +1000, Sridhar Dhanapalan wrote: On 16 June 2012 17:08, James Cameron qu...@laptop.org wrote: That means the hang should not exceed 15 seconds. ?Is this what you find? ?If not, then this casts doubt on your solution. I'm going to propose something extremely hackish: [...] Just to remind you that I'm still interested to know if the hang you observe exceeds 15 seconds or not. I've not had the time to reproduce this hang yet. Building a mental model of the problem is important to me, because I can sometimes resolve a problem if I have a good model. Yes; we have left it for several minutes and no shutdown has occurred. If you disable the boot/shutdown animation, the shutdown sequence stops at this: http://dev.laptop.org.au/attachments/download/914/hang-on-shutdown.jpg That image is an attachment on the main issue: http://dev.laptop.org.au/issues/1033 The XO-1.75 CPU has a hardware watchdog that could be used for this, but you aren't likely to ever have a heat problem with XO-1.75. That is interesting. Why is that? Thanks, Sridhar ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: On XO-1.5 with 11.3.0/11.3.1 -- hang during shutdown?
Thanks for your reply! On Mon, Jun 25, 2012 at 11:16:26AM +1000, Sridhar Dhanapalan wrote: On 21 June 2012 16:14, James Cameron qu...@laptop.org wrote: On Thu, Jun 21, 2012 at 02:37:35PM +1000, Sridhar Dhanapalan wrote: On 16 June 2012 17:08, James Cameron qu...@laptop.org wrote: That means the hang should not exceed 15 seconds. ?Is this what you find? ?If not, then this casts doubt on your solution. I'm going to propose something extremely hackish: [...] Just to remind you that I'm still interested to know if the hang you observe exceeds 15 seconds or not. ?I've not had the time to reproduce this hang yet. ?Building a mental model of the problem is important to me, because I can sometimes resolve a problem if I have a good model. Yes; we have left it for several minutes and no shutdown has occurred. Ooh, I'm surprised. This observation, and the statistical results from your temporary solution (a delay), implies a combination effect, of both the processes not yet terminated, and the umount, leading to a process hang of umount. I can't think of a hack that would meet the requirements: - survive the process deletion steps, and - detect the stalled umount process. I guess you might try remounting the filesystem -o sync, just to further shift the timing. The problem needs a kernel developer to reproduce it. Do you have a way to encourage the problem to occur? If it can be made to occur on a higher percentage of shutdowns, it becomes easier to debug. For instance, there is a two second delay in the code, so does the hang occur more frequently if this is reduced to zero? The XO-1.75 CPU has a hardware watchdog that could be used for this, but you aren't likely to ever have a heat problem with XO-1.75. That is interesting. Why is that? I take it you mean why won't you have a heat problem with XO-1.75. There are two new characteristics of the XO-1.75 over the XO-1.5: 1. the maximum power draw of the XO-1.75 at full utilisation is a long way below that of the XO-1.5. In a scenario where the laptop is powered on and insulated from cooling air flow, this means: 1.a. the temperature rise toward equilibrium will be slower, 1.b. the equilibrium temperature will be lower for a given level of insulation, (stacking, or cloth covers, or both), 1.c. the insulation will have to be far greater to achieve the same equilibrium temperature. 2. the XO-1.75 has a thermal protection feature that forces the power off if the temperature of the CPU exceeds 85 degrees C, rather than slowing or stopping the CPU as on XO-1.5. In a scenario where the laptop is powered on and insulated from cooling air flow, this means: 2.a. the temperature rise will be interrupted by a sudden loss of input heat, rather than be slowed by a gradual loss of input heat, 2.b. the insulation will have to be far far greater to achieve the same equilibrium temperature. In this scenario, the heat spreader has very little bearing on the matter. The heat spreader relies on cooling air flow to the top of the case. If there is no air flow, the heat spreader is ineffective. The new thermal protection feature isn't a perfect protection; the battery charge circuit remains powered. So a laptop held between very good insulation (e.g. thick polystyrene with sealed edges) with a flat battery will still heat up, but not nearly as much as one with an active CPU. (Please, test this yourselves with an IR thermometer. If you don't have one, the closest in Sydney to you would be at the Jaycar store at 127 York St.) -- James Cameron http://quozl.linux.org.au/ ___ Devel mailing list Devel@lists.laptop.org http://lists.laptop.org/listinfo/devel
Re: [Server-devel] ARM on XS -- how can I integrate my work?
On Jun 24, 2012, at 7:14 AM, George Hunt wrote: Hi all, I'm not done yet, but I've been making progress on porting XS code to ARM by making modifications to DSD's XS-0.7. Upon his suggestion, I have been basing my work on the srpms posted at http://xs-dev.laptop.org/xsrepos/stable/olpc/xs-0.7/source/. I'm following Peter Robinson's suggestion, and using FC17 armv7hl snapshots as a base. The systemd startup requires mostly trivial changes from the old systemV mechanisms. Now that I've got some of the services running, I'm wondering how to contribute to the XS codebase. What I'd prefer is to contribute deltas from XS-0.7 that use `uname -p` to enable the appropriate path through the startup scripts. But I think contributing deltas presupposes that I'm working off of a git repository. Earlier, I started using the git sources at dev.laptop.org, and I discovered that there did not appear to be an obvious set of git repos, corresponding to XS-0.7. Paths for repos that had the most recent changes included: /packages/ /projects/ /bios-crypto/ /users/martin/ Any suggestions on how we should proceed? George ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel George, A while ago I asked for clarification about which git branches where the correct ones to pull from and never got a satisfactory answer. I had a few things I wanted to submit as patches but have been holding back on it. Meanwhile I had a few equipment failures and had to rebuild some drives and used my main ARM system for testing the evolving F17 for ARM which has finally gone GA. ( Along with some disruption from a flood which fortunately missed the XOs). I think the approach overall that I have been taking is a bit different from yours as my long term goal is to support the 2 current ARM archs that Fedora currently is built for and trying a few other new things to make the components used to be more similar to what is upstream. This is possibly a more experimental approach than you are using. Part of my plan is to set up my own ARM based Koji system. I have enough ARM devices to do this but need to order one more to make it more viable. Maybe we can compare notes in October...at the OLPC-SF 2012 Community Summit. regards, Robert H rihowa...@gmail.com linux - the best things in life are free ___ Server-devel mailing list Server-devel@lists.laptop.org http://lists.laptop.org/listinfo/server-devel
