On Thursday 09 November 2017 09:19 AM, Mahesh Kumar wrote:
Hi,
On Thursday 09 November 2017 01:30 AM, Ville Syrjälä wrote:
On Wed, Nov 08, 2017 at 10:39:59AM +0530, Mahesh Kumar wrote:
Hi,
On Tuesday 07 November 2017 11:57 PM, Chris Wilson wrote:
clang spots
drivers/gpu/drm/i915/intel_pm.c:4655:6: warning: variable
'trans_min' is used uninitialized whenever 'if' condition is false
[-Wsometimes-uninitialized]
if (INTEL_GEN(dev_priv) >= 10)
but fortunately for us we skip the function unless on a gen10+ device.
However, to keep the function generic in case we do want to
re-enable it
for gen9 again, initialise trans_min to 0.
References: ca47667f523e ("drm/i915/gen10: Calculate and enable
transition WM")
Signed-off-by: Chris Wilson <ch...@chris-wilson.co.uk>
Cc: Mahesh Kumar <mahesh1.ku...@intel.com>
Cc: Maarten Lankhorst <maarten.lankho...@linux.intel.com>
Cc: Jani Nikula <jani.nik...@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahti...@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.v...@intel.com>
Cc: Ville Syrjälä <ville.syrj...@linux.intel.com>
---
drivers/gpu/drm/i915/intel_pm.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/i915/intel_pm.c
b/drivers/gpu/drm/i915/intel_pm.c
index b75c4cf074ff..40da5001be28 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4652,6 +4652,7 @@ static void skl_compute_transition_wm(struct
intel_crtc_state *cstate,
if (!dev_priv->ipc_enabled)
goto exit;
+ trans_min = 0;
if (INTEL_GEN(dev_priv) >= 10)
trans_min = 4;
BSpec WA section tells not to enable transition watermark for any GEN-9
platforms (that was the assumption with this patch)
But anyway trans_min value for GEN9 is 14 blocks, IMO adding else case
with trans_min = 14; will be logical solution to this.
Bspec is telling me that 14 is the correct value for gen10 as well.
Looks like the 4 came back from the future.
Thanks Ville for correcting this, I checked the BSpec again, yes for
gen-10 as well value is 14, looks like I read 4 instead of 14 earlier.
So we can always init trans_min = 14.
Further debugging reveals this is a nasty BSpec update, until GEN9/10 WM
programming was is same page this value was 4 for GEN-10 but after
moving it to new page the value is updated to 14.
anyway I sent a query to HW team regarding same.
-Mahesh
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