[Intel-gfx] [PATCH 0/6] eDP DRRS based on frontbuffer tracking

[Daniel Vetter]

On Fri, Feb 13, 2015 at 03:32:58PM +0530, Ramalingam C wrote:
> This series includes a preparation patch for drrs support across differnt
> platforms in intel_dp_set_m_n along with last 5 pending patches of V3 eDP
> DRRS patch series.
> 
> New series is submitted to make the review more comfortable and
> to display the dependancy of the patches explicitly.
> 
> Durgadoss R (1):
>   drm/i915: Enable eDP DRRS for CHV
> 
> Ramalingam C (1):
>   drm/i915: Add support for DRRS in intel_dp_set_m_n
> 
> Vandana Kannan (4):
>   drm/i915/bdw: Add support for DRRS to switch RR
>   drm/i915: Support for RR switching on VLV
>   Documentation/drm: DocBook integration for DRRS
>   drm/i915: Add debugfs entry for DRRS

Ok I've reviewed the locking for DRRS quickly now that it's all merged and
it's deadlock-y:

intel_edp_drrs_downclock_work grabs the drrs mutex. But in the disable
function we cancel that work and wait for that to complete (cancel_sync)
while holding the lock.

Which means if the async work is running this will deadlock. The work
cancel must be moved out of the critical section, and the work must
double-check (after taking the lock) that drrs hasn't been disabled
meanwhile (by checking drrs.dp, which we already do). intel_psr.c contains
all that logic as an example.

While you do that follow-up patch could we extract the drrs code into a
new intel_drrs.c file? That would also simplify the kerneldoc includes a
bit.

Cheers, Daniel
> 
>  Documentation/DocBook/drm.tmpl       |   11 ++++
>  drivers/gpu/drm/i915/i915_debugfs.c  |   99 ++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_reg.h      |    1 +
>  drivers/gpu/drm/i915/intel_display.c |   32 ++++++---
>  drivers/gpu/drm/i915/intel_dp.c      |  121 ++++++++++++++++++++++++++++++++--
>  drivers/gpu/drm/i915/intel_drv.h     |   22 ++++++-
>  6 files changed, 273 insertions(+), 13 deletions(-)
> 
> -- 
> 1.7.9.5
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch