[Intel-gfx] [PATCH] VPG [BDW] drm/i915/bdw: DP aux channel control timeout change

[Daniel Vetter]

On Tue, Nov 26, 2013 at 01:41:57PM +0530, kirankumar wrote:
> changing DP AUX control timeout to 600 instead of 400 for BDW.

DP spec says 400 us, so a notch more context in the commit message would
be appreciated. E.g. if this is used to work around dp aux failures, then
the commit message _must_ mention this. I need this to asses in which
branch to put the patch.

Also we still have occasional dp aux woes on older platforms. Do we need a
similar timeout extension for those, too?

Remember people: The commit message must explain _why_ something needs to
change. If you feel like you need to explain the what of your change, your
code probably needs to be rewritten to be esier to understand.

Cheers, Daniel

> 
> Change-Id: Id507ef35490e12bbd896492c9da24d0db367bf1a
> Signed-off-by: kirankumar <kiran.s.kumar at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_dp.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ae2a057..953a3f6 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -351,7 +351,7 @@ intel_dp_aux_ch(struct intel_dp *intel_dp,
>  		I915_WRITE(ch_ctl,
>  			   DP_AUX_CH_CTL_SEND_BUSY |
>  			   (has_aux_irq ? DP_AUX_CH_CTL_INTERRUPT : 0) |
> -			   DP_AUX_CH_CTL_TIME_OUT_400us |
> +			   DP_AUX_CH_CTL_TIME_OUT_600us |
>  			   (send_bytes << DP_AUX_CH_CTL_MESSAGE_SIZE_SHIFT) |
>  			   (precharge << DP_AUX_CH_CTL_PRECHARGE_2US_SHIFT) |
>  			   (aux_clock_divider << DP_AUX_CH_CTL_BIT_CLOCK_2X_SHIFT) |
> -- 
> 1.7.9.5
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch