[Intel-gfx] [PATCH 1/3] drm/i915: Sink rate read should be saved in deca-kHz

[Jani Nikula]

On Thu, 07 May 2015, Sonika Jindal <sonika.jindal at intel.com> wrote:
> The sink rate read from supported link rate table is in KHz as per spec
> while in drm, the saved clock is in deca-KHz. So divide the link rate by
> 10 before storing.

Please refer to the commit which broke things. git blame is your
friend. We need the information to know which kernel version the bug has
landed or is about to land to, so we can queue the fix in the same
place.

If developers don't do this, maintainers will have to anyway, which
doesn't scale well, which leads to grumpy maintainers. ;)

Thanks,
Jani.


>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Signed-off-by: Sonika Jindal <sonika.jindal at intel.com>
> ---
> Just resending it along with the other intermediate link rate patches
> (It was posted orginally on 21st April)
>
> Thanks,
> Sonika
>
>  drivers/gpu/drm/i915/intel_dp.c |    3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index bacdec5..6bd5afb 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3906,7 +3906,8 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
>  			if (val == 0)
>  				break;
>  
> -			intel_dp->sink_rates[i] = val * 200;
> +			/* Value read is in kHz while drm clock is saved in deca-kHz */
> +			intel_dp->sink_rates[i] = (val * 200) / 10;
>  		}
>  		intel_dp->num_sink_rates = i;
>  	}
> -- 
> 1.7.10.4
>
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-- 
Jani Nikula, Intel Open Source Technology Center