On Tue, Nov 17, 2015 at 10:18:41PM +0100, Daniel Vetter wrote: > If we can't acquire dev->struct_mutex we need to fail runtime suspend, > at least with the current design. Currently we do that using -EAGAIN, > but that upsets the pm core, resulting in the occasional fail testcase > in our CI with the following dmesg dirt: > > pci_pm_runtime_suspend(): intel_runtime_suspend+0x0/0x240 [i915] returns -11 > > Chris has some ideas to improve this, but for now just shut up the > error. > > Cc: Paulo Zanoni <[email protected]> > Cc: Chris Wilson <[email protected]> > Signed-off-by: Daniel Vetter <[email protected]> > --- > drivers/gpu/drm/i915/i915_drv.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c > index 5a70aca71d6b..ab8ffbc48e2d 100644 > --- a/drivers/gpu/drm/i915/i915_drv.c > +++ b/drivers/gpu/drm/i915/i915_drv.c > @@ -1497,8 +1497,7 @@ static int intel_runtime_suspend(struct device *device) > * We could deadlock here in case another thread holding struct_mutex > * calls RPM suspend concurrently, since the RPM suspend will wait > * first for this RPM suspend to finish. In this case the concurrent > - * RPM resume will be followed by its RPM suspend counterpart. Still > - * for consistency return -EAGAIN, which will reschedule this suspend. > + * RPM resume will be followed by its RPM suspend counterpart. > */ > if (!mutex_trylock(&dev->struct_mutex)) { > DRM_DEBUG_KMS("device lock contention, deffering suspend\n"); > @@ -1508,7 +1507,8 @@ static int intel_runtime_suspend(struct device *device) > */ > pm_runtime_mark_last_busy(device); > > - return -EAGAIN; > + /* Fail silently to avoid upsetting the pm core. */ > + return 0;
So the core will assume we're now suspended and then resume gets called while we're still powered on. Sounds like a bad plan to me. I'm especially worried about VLV here with its GT no wake dance and manual save/restore. > } > /* > * We are safe here against re-faults, since the fault handler takes > -- > 2.5.1 > > _______________________________________________ > Intel-gfx mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/intel-gfx
