Re: [PATCH 1/5] drm/i915/display: Fix the plane max height and width limits

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Oct 25, 2024 at 11:31:32AM +0530, Suraj Kandpal wrote:
> Fix the plane max height and width limits taking into account the
> joined pipe limits too.
> 
> Bspec: 28692, 49199, 68858
> Fixes: 63dc014e37b9 ("drm/i915/dp: Allow big joiner modes in intel_dp_mode_valid(), v3.")
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 19 ++++++++++++++++---
>  1 file changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index ef1436146325..fc578af4f394 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -8450,9 +8450,22 @@ intel_mode_valid_max_plane_size(struct drm_i915_private *dev_priv,
>  	 * plane so let's not advertize modes that are
>  	 * too big for that.
>  	 */
> -	if (DISPLAY_VER(dev_priv) >= 11) {
> -		plane_width_max = 5120 * num_joined_pipes;
> -		plane_height_max = 4320;
> +	if (DISPLAY_VER(dev_priv) >= 20) {
> +		if (num_joined_pipes > 1) {
> +			plane_width_max = 8192;
> +			plane_height_max = 4800;
> +		} else {
> +			plane_width_max = 5120;
> +			plane_height_max = 4096;

The joiner operates on horizontal lines. Why would the
vertical resolution change here?

And this is breaking ultrajoiner now.

Frankly I have a hard time believing that there are any extra
limits on plane size imposed by the hardware for joined pipes.
If there is some kind of maximum width limit then it must be
coming from the joiner itself (eg. max line buffer width) and
not from the planes. So I think this is the wrong place to
handle that.

> +		}
> +	} else if (DISPLAY_VER(dev_priv) >= 11) {
> +		if (num_joined_pipes > 1) {
> +			plane_width_max = 7680;
> +			plane_height_max = 4320;
> +		} else {
> +			plane_width_max = 5120;
> +			plane_height_max = 4096;
> +		}
>  	} else {
>  		plane_width_max = 5120;
>  		plane_height_max = 4096;
> -- 
> 2.34.1

-- 
Ville Syrjälä
Intel