Hi, any update on this/do you guys need any more information here? Would very much like to get this upstream On Fri, 2019-03-22 at 06:30 -0500, Bjorn Helgaas wrote: > On Thu, Mar 21, 2019 at 05:48:19PM -0500, Bjorn Helgaas wrote: > > On Wed, Mar 13, 2019 at 06:25:02PM -0400, Lyude Paul wrote: > > > On Fri, 2019-02-15 at 16:17 -0500, Lyude Paul wrote: > > > > On Thu, 2019-02-14 at 18:43 -0600, Bjorn Helgaas wrote: > > > > > On Tue, Feb 12, 2019 at 05:02:30PM -0500, Lyude Paul wrote: > > > > > > On a very specific subset of ThinkPad P50 SKUs, particularly > > > > > > ones that come with a Quadro M1000M chip instead of the M2000M > > > > > > variant, the BIOS seems to have a very nasty habit of not > > > > > > always resetting the secondary Nvidia GPU between full reboots > > > > > > if the laptop is configured in Hybrid Graphics mode. The > > > > > > reason for this happening is unknown, but the following steps > > > > > > and possibly a good bit of patience will reproduce the issue: > > > > > > > > > > > > 1. Boot up the laptop normally in Hybrid graphics mode > > > > > > 2. Make sure nouveau is loaded and that the GPU is awake > > > > > > 2. Allow the nvidia GPU to runtime suspend itself after being idle > > > > > > 3. Reboot the machine, the more sudden the better (e.g sysrq-b may > > > > > > help) > > > > > > 4. If nouveau loads up properly, reboot the machine again and go > > > > > > back to > > > > > > step 2 until you reproduce the issue > > > > > > > > > > > > This results in some very strange behavior: the GPU will quite > > > > > > literally be left in exactly the same state it was in when the > > > > > > previously booted kernel started the reboot. This has all > > > > > > sorts of bad sideaffects: for starters, this completely breaks > > > > > > nouveau starting with a mysterious EVO channel failure that > > > > > > happens well before we've actually used the EVO channel for > > > > > > anything: > > > > Thanks for the hybrid tutorial (snipped from this response). IIUC, > > what you said was that in hybrid mode, the Intel GPU drives the > > built-in display and the Nvidia GPU drives any external displays and > > may be used for DRI PRIME rendering (whatever that is). But since you > > say the Nvidia device gets runtime suspended, I assume there's no > > external display here and you're not using DRI PRIME. > > > > I wonder if it's related to the fact that the Nvidia GPU has been > > runtime suspended before you do the reboot. Can you try turning of > > runtime power management for the GPU by setting the runpm module > > parameter to 0? I *think* this would be booting with > > "nouveau.runpm=0". > > Sorry, I wasn't really thinking here. You already *said* this is > related to runtime suspend. It only happens when the Nvidia GPU has > been suspended. > > I don't know that much about suspend, but ISTR seeing comments about > resuming devices before we shutdown. If we do that, maybe there's > some kind of race between that resume and the reboot? > > Bjorn -- Cheers, Lyude Paul
