On Tue, Apr 24, 2018 at 06:19:16PM +0300, Imre Deak wrote:
commit 5e1df40f40ee45a97bb1066c3d71f0ae920a9672 upstream.
Currently we see sporadic timeouts during CDCLK changing both on BXT and GLK as reported by the Bugzilla: ticket. It's easy to reproduce this by changing the frequency in a tight loop after blanking the display. The upper bound for the completion time is 800us based on my tests, so increase it from the current 500us to 2ms; with that I couldn't trigger the problem either on BXT or GLK.
Note that timeouts happened during both the change notification and the voltage level setting PCODE request. (For the latter one BSpec doesn't require us to wait for completion before further HW programming.)
This issue is similar to commit 2c7d0602c815 ("drm/i915/gen9: Fix PCODE polling during CDCLK change notification") but there the PCODE request does complete (as shown by the mbox busy flag), only the reply we get from PCODE indicates a failure. So there we keep resending the request until a success reply, here we just have to increase the timeout for the one PCODE request we send.
v2:
- s/snb_pcode_request/sandybridge_pcode_write_timeout/ (Ville)
Cc: Chris Wilson chris@chris-wilson.co.uk Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: stable@vger.kernel.org # v4.9 Acked-by: Chris Wilson chris@chris-wilson.co.uk (v1) Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103326 Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Imre Deak imre.deak@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20180130142939.17983-1-imre.de... (cherry picked from commit e76019a81921e87a4d9e7b3d86102bc708a6c227) Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com (Rebased for v4.9 stable tree due to upstream intel_cdclk.c, cdclk_state and pcu_lock change) Signed-off-by: Imre Deak imre.deak@intel.com
drivers/gpu/drm/i915/i915_drv.h | 6 +++++- drivers/gpu/drm/i915/intel_display.c | 9 +++++---- drivers/gpu/drm/i915/intel_pm.c | 6 +++--- 3 files changed, 13 insertions(+), 8 deletions(-)
Now queued up, thanks.
greg k-h