[Nouveau] [REGRESSION] nouveau: 30 second boot hang after commit 2b700825e
Alexandre Courbot
gnurou at gmail.com
Wed Mar 2 03:22:30 UTC 2016
On Tue, Mar 1, 2016 at 4:45 PM, Eric Biggers <ebiggers3 at gmail.com> wrote:
> Hello,
>
> I am encountering a 30 second hang during boot, in the Xorg process just before
> the display manager comes up. I have bisected the problem to the following
> commit:
>
> commit 2b700825e7a7702fb862edba1262c98040dc1bf6
> Author: Ben Skeggs <bskeggs at redhat.com>
> Date: Thu Aug 20 14:54:22 2015 +1000
>
> drm/nouveau/mc: move device irq handling to platform-specific code
>
> The hang only occurs with CONFIG_DEBUG_SHIRQ=y, which is why I didn't notice it
> sooner (I don't usually compile my kernels with that option).
>
> Based on the log output with drm_debug=0x3f, the hang is occurring in
> nouveau_gem_ioctl_cpu_prep(), where there is a 30 second timeout.
>
> This is on an "Optimus" laptop which has both an Intel and an Nvidia card. I
> understand that the Nvidia card is being disabled automatically, and only the
> Intel one is used; but the nouveau driver obviously still does a few things
> either way. The Nvidia hardware is: NVIDIA Corporation GK107GLM [Quadro K1100M]
> (rev a1).
>
> I don't have the expertise to fully assess the suspect commit. Any thoughts as
> to the root cause of this problem? Is there any other information I can
> provide?
This line of nouveau_gem_ioctl_cpu_prep() seems to match a 30-seconds timeout:
lret = reservation_object_wait_timeout_rcu(nvbo->bo.resv,
write, true, 30 * HZ);
Without the commit you mentioned, and with CONFIG_DEBUG_SHIRQ enabled,
do you also see this error? Is it absolutely reproducable?
Also, can you give more details about the X configuration? (display
driver, PRIME configuration, how the NVIDIA GPU is used by your
display manager, etc.)
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