diff options
| author |   Mika Kuoppala <mika.kuoppala@linux.intel.com> | 2017-11-02 11:48:36 +0200 |
|---|---|---|
| committer | Mika Kuoppala <mika.kuoppala@linux.intel.com> | 2017-11-02 12:40:21 +0200 |
| commit | 7130630323c562597191653560963e61c5bd0f57 (patch) | |
| tree | 0db7cadae69551366dc6823e117ca013dcdbd1e5 /drivers/gpu/drm/i915/i915_reg.h | |
| parent | drm/i915/guc: Add support for reset engine using GuC commands (diff) | |
| download | linux-dev-7130630323c562597191653560963e61c5bd0f57.tar.xz linux-dev-7130630323c562597191653560963e61c5bd0f57.zip | |
drm/i915: Use fallback forcewake if primary ack missing
There is a possibility on gen9 hardware to miss the forcewake ack
message. The recommended workaround is to use another free
bit and toggle it until original bit is successfully acknowledged.
Some future gen9 revs might or might not fix the underlying issue but
using fallback forcewake bit dance can be considered as harmless:
without the ack timeout we never reach the fallback bit forcewake.
Thus as of now we adopt a blanket approach for all gen9 and leave
the bypassing the fallback bit approach for future patches if
corresponding hw revisions do appear.
Commit 83e3337204b2 ("drm/i915: Increase maximum polling time to 50ms
for forcewake request/clear ack") did increase the forcewake timeout.
If the issue was a delayed ack, future work could include finding
a suitable timeout value both for primary ack and reserve toggle
to reduce the worst case latency.
v2: use bit 15, naming, comment (Chris), only wait fallback ack
v3: fix return on fallback, backoff after fallback write (Chris)
v4: udelay on first pass, grammar (Chris)
v4: s/reserve/fallback
References: HSDES #1604254524
References: https://bugs.freedesktop.org/show_bug.cgi?id=102051
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Sagar Arun Kamble <sagar.a.kamble@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20171102094836.2506-1-mika.kuoppala@linux.intel.com
Diffstat (limited to 'drivers/gpu/drm/i915/i915_reg.h')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_reg.h | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 8c775e96b4e4..f0f8f6059652 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -7774,8 +7774,9 @@ enum { #define FORCEWAKE_ACK_MEDIA_GEN9 _MMIO(0x0D88) #define FORCEWAKE_ACK_RENDER_GEN9 _MMIO(0x0D84) #define FORCEWAKE_ACK_BLITTER_GEN9 _MMIO(0x130044) -#define FORCEWAKE_KERNEL 0x1 -#define FORCEWAKE_USER 0x2 +#define FORCEWAKE_KERNEL BIT(0) +#define FORCEWAKE_USER BIT(1) +#define FORCEWAKE_KERNEL_FALLBACK BIT(15) #define FORCEWAKE_MT_ACK _MMIO(0x130040) #define ECOBUS _MMIO(0xa180) #define FORCEWAKE_MT_ENABLE (1<<5) |