[PATCH 1/2] drm/msm/dsi: improve/fix dsc pclk calculation

[Jonathan Marek]

On 10/5/24 12:31 PM, Konrad Dybcio wrote:
> On 5.10.2024 4:38 PM, Jonathan Marek wrote:
>> drm_mode_vrefresh() can introduce a large rounding error, avoid it.
>>
>> Signed-off-by: Jonathan Marek <jonathan at marek.ca>
>> ---
>>   drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
>> index 185d7de0bf376..1205aa398e445 100644
>> --- a/drivers/gpu/drm/msm/dsi/dsi_host.c
>> +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c
>> @@ -542,7 +542,7 @@ static unsigned long dsi_adjust_pclk_for_compression(const struct drm_display_mo
>>   
>>   	int new_htotal = mode->htotal - mode->hdisplay + new_hdisplay;
>>   
>> -	return new_htotal * mode->vtotal * drm_mode_vrefresh(mode);
>> +	return mult_frac(mode->clock * 1000u, new_htotal, mode->htotal);
> 
> This seems to ignore mult/div by two on certain mode flags.. is that
> intended?
> 
> Konrad
> 

It is intended - those flags are not relevant to DSI panels, and DSC 
pclk adjustment is only about how DSC affects htotal.