[Intel-gfx] [PATCH 3/9] drm/i915: use the mode->htotal to calculate linetime watermarks

[Paulo Zanoni]

2013/5/21 Daniel Vetter <daniel at ffwll.ch>:
> On Fri, May 03, 2013 at 05:23:39PM -0300, Paulo Zanoni wrote:
>> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>
>> ... instead of mode->crtc_display. The spec says "pipe horizontal
>> total number of pixels" and the "Haswell Watermark Calculator" tool
>> uses the "Pipe H Total" instead of "Pipe H Src" as the value.
>>
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_pm.c |    2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
>> index d056bc9..4cc5f99 100644
>> --- a/drivers/gpu/drm/i915/intel_pm.c
>> +++ b/drivers/gpu/drm/i915/intel_pm.c
>> @@ -2035,7 +2035,7 @@ haswell_update_linetime_wm(struct drm_device *dev, struct drm_crtc *crtc)
>>        * row at the given clock rate, multiplied by 8.
>>        * */
>>       temp |= PIPE_WM_LINETIME_TIME(
>> -             ((mode->crtc_hdisplay * 1000) / mode->clock) * 8);
>> +             ((mode->htotal * 1000) / mode->clock) * 8);
>
> Big question: What's the right value for interlaced modes? On progressive
> mode crtc_ mode values match the non-crtc_ prefixed ones, but not so much
> for interlaced modes ... So if your tool expects something resembling what
> we program into the pipe registers, we need to change this again.
>
> Merged for now since the spec explicitly says "pixels", but I'd like
> someone to double-check this.

The WM calculator tool says:
"Pipe H total is found in PIPE_HTOTAL horizontal field".

But mode->htotal and mode->crtc_htotal are the same even when the mode
is interlaced. So at least the values we compute are correct. I could
write a follow-up patch updating this if you want.

> -Daniel
>>
>>       /* IPS watermarks are only used by pipe A, and are ignored by
>>        * pipes B and C.  They are calculated similarly to the common
>> --
>> 1.7.10.4
>>
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>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch



-- 
Paulo Zanoni