Re: [regression drm/noveau] suspend to ram -> BOOM: exception RIP: drm_calc_vbltimestamp_from_scanoutpos+335

From: Tobias Klausmann
Date: Fri Jul 14 2017 - 11:05:49 EST

On 7/14/17 3:41 PM, Mike Galbraith wrote:
On Fri, 2017-07-14 at 15:36 +0200, Mike Galbraith wrote:
ÂAll DRM did was to slip a
WARN_ON_ONCE() that nouveau triggers into a kernel module where such
things no longer warn, they blow the box out of the water.
BTW, turn that irksome WARN_ON_ONCE() in drivers/gpu/drm/drm_vblank.c
into a WARN_ONCE(), and all is peachy, you get the warning, box lives.

drivers/gpu/drm/drm_vblank.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_vblank.c
+++ b/drivers/gpu/drm/drm_vblank.c
@@ -605,7 +605,8 @@ bool drm_calc_vbltimestamp_from_scanoutp
if (mode->crtc_clock == 0) {
DRM_DEBUG("crtc %u: Noop due to uninitialized mode.\n", pipe);
- WARN_ON_ONCE(drm_drv_uses_atomic_modeset(dev));
+ WARN_ONCE(drm_drv_uses_atomic_modeset(dev), "%s: report me.\n",
+ dev->driver->name);
return false;


confirmed this helps saving the box, but we still have to find the root cause! Backtrace with the above fix applied (and the one which came in with the latest drm-fixes merge)!