Re: [PATCH] drm/arm/malidp: Preserve LAYER_FORMAT contents when setting format

From: Liviu Dudau
Date: Thu Apr 12 2018 - 06:18:04 EST


On Tue, Apr 10, 2018 at 07:25:03PM +0100, Ayan Kumar Halder wrote:
> On some Mali-DP processors, the LAYER_FORMAT register contains fields
> other than the format. These bits were unconditionally cleared when
> setting the pixel format, whereas they should be preserved at their
> reset values.
>
> Reported-by: Brian Starkey <brian.starkey@xxxxxxx>
> Reported-by: Liviu Dudau <liviu.dudau@xxxxxxx>
> Signed-off-by: Ayan Kumar halder <ayan.halder@xxxxxxx>

Acked-by: Liviu Dudau <liviu.dudau@xxxxxxx>

Thanks for catching this in testing!

Best regards,
Liviu

> ---
> drivers/gpu/drm/arm/malidp_planes.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/arm/malidp_planes.c b/drivers/gpu/drm/arm/malidp_planes.c
> index 7a44897..4af3c1f 100644
> --- a/drivers/gpu/drm/arm/malidp_planes.c
> +++ b/drivers/gpu/drm/arm/malidp_planes.c
> @@ -23,6 +23,7 @@
>
> /* Layer specific register offsets */
> #define MALIDP_LAYER_FORMAT 0x000
> +#define LAYER_FORMAT_MASK 0x3f
> #define MALIDP_LAYER_CONTROL 0x004
> #define LAYER_ENABLE (1 << 0)
> #define LAYER_FLOWCFG_MASK 7
> @@ -337,7 +338,9 @@ static void malidp_de_plane_update(struct drm_plane *plane,
> dest_w = plane->state->crtc_w;
> dest_h = plane->state->crtc_h;
>
> - malidp_hw_write(mp->hwdev, ms->format, mp->layer->base);
> + val = malidp_hw_read(mp->hwdev, mp->layer->base);
> + val = (val & ~LAYER_FORMAT_MASK) | ms->format;
> + malidp_hw_write(mp->hwdev, val, mp->layer->base);
>
> for (i = 0; i < ms->n_planes; i++) {
> /* calculate the offset for the layer's plane registers */
> --
> 2.7.4
>

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