linux/drivers/gpu
Mika Kuoppala 99106bc17e drm/i915: Do graphics device reset under forcewake
We have a timed release of a forcewake when using
I915_READ/WRITE macros. wait_for() macro will go to quite
long sleep if the first read doesn't satisfy the condition for
successful exit. With these two interacting, it is possible that
we lose the forcewake during the wait_for() and the subsequent read
will reaquire forcewake.

Further experiments with skl shows that when we lose forcewake,
we lose the reset request we submitted. So reset request register
is not power context saved.

Grab forcewakes for all engines before starting the reset/request
dance so that all requests stay valid for the duration of reset
requisition across all the engines.

v2: Add comment on power well sleeps. Wrap the reset handling
    under forcewake instead of just reset requests (Chris)

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92774
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Tomi Sarvela <tomix.p.sarvela@intel.com> (v1, v2)
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1446721898-1450-1-git-send-email-mika.kuoppala@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2015-11-05 15:31:07 +02:00
..
drm drm/i915: Do graphics device reset under forcewake 2015-11-05 15:31:07 +02:00
host1x gpu: host1x: mipi: Power down regulators when unused 2015-08-13 13:47:21 +02:00
ipu-v3 gpu/drm: Kill off set_irq_flags usage 2015-09-16 16:53:38 +02:00
vga vga_switcheroo: Set active attribute to false for audio clients 2015-09-24 20:14:25 +02:00
Makefile