On Wed, Oct 15, 2025 at 12:15:15AM -0300, Gustavo Sousa wrote:
> When reading memory latencies for watermark calculations, previous
> display releases instructed to apply an adjustment of adding a certain
> value (e.g. 6us) to all levels when the level 0's memory latency read
> from hardware was zero.
> 
> For Xe3p_LPD, the instruction is to always use 6us for level 0 and to
> add that value to the other levels.  Update adjust_wm_latency()
> accordingly.
> 
> Bspec: 68986, 69126
> Signed-off-by: Gustavo Sousa <[email protected]>
> ---
>  drivers/gpu/drm/i915/display/skl_watermark.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/skl_watermark.c 
> b/drivers/gpu/drm/i915/display/skl_watermark.c
> index 41f64e347436..88342d07727f 100644
> --- a/drivers/gpu/drm/i915/display/skl_watermark.c
> +++ b/drivers/gpu/drm/i915/display/skl_watermark.c
> @@ -3249,6 +3249,13 @@ adjust_wm_latency(struct intel_display *display)
>  
>       make_wm_latency_monotonic(display);
>  
> +     /*
> +      * Xe3p asks to ignore wm[0] read from the register and always
> +      * use the adjustment done with read_latency.
> +      */
> +     if (DISPLAY_VER(display) >= 35)
> +             wm[0] = 0;

make_wm_latency_monotonic() already used wm[0]. I think this
needs to be the very first thing you do in adjust_wm_latency().

> +
>       /*
>        * WaWmMemoryReadLatency
>        *
> 
> -- 
> 2.51.0

-- 
Ville Syrjälä
Intel

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