On Sun, Aug 09, 2020 at 12:31:19AM +0200, Linus Walleij wrote:
> The pixel fetcher FIFO depth was just hardcoded to 48
> which works fine as long as the framebuffer is 32BPP
> and the DSI output is RGB888.
>
> We will need more elaborate handling for some buffer
> formats and displays, so start to improve this function
> by setting reasonable defaults for 32, 24 and 16 BPP
> framebuffers.
>
> Cc: newbytee@xxxxxxxxxxxxxx
> Cc: Stephan Gerhold <stephan@xxxxxxxxxxx>
> Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
> ---
> drivers/gpu/drm/mcde/mcde_display.c | 34 +++++++++++++++++++++++++----
> 1 file changed, 30 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/mcde/mcde_display.c b/drivers/gpu/drm/mcde/mcde_display.c
> index cac660ac8803..cbc7c0c4955a 100644
> --- a/drivers/gpu/drm/mcde/mcde_display.c
> +++ b/drivers/gpu/drm/mcde/mcde_display.c
> @@ -333,7 +333,7 @@ static void mcde_configure_overlay(struct mcde *mcde, enum mcde_overlay ovl,
> enum mcde_extsrc src,
> enum mcde_channel ch,
> const struct drm_display_mode *mode,
> - u32 format)
> + u32 format, int cpp)
Note that format->cpp is a bit outdated, since it doesn't work for planar
stuff. But I guess not a problem for you (for now at least). Blocky
formats like yuv don't set format->cpp, or at least not in the way you'd
expect.
Anyway now idea on the hw, but patch looks reasonable.
Acked-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
> {
> u32 val;
> u32 conf1;
> @@ -342,6 +342,7 @@ static void mcde_configure_overlay(struct mcde *mcde, enum mcde_overlay ovl,
> u32 ljinc;
> u32 cr;
> u32 comp;
> + u32 pixel_fetcher_watermark;
>
> switch (ovl) {
> case MCDE_OVERLAY_0:
> @@ -426,8 +427,33 @@ static void mcde_configure_overlay(struct mcde *mcde, enum mcde_overlay ovl,
> format);
> break;
> }
> - /* The default watermark level for overlay 0 is 48 */
> - val |= 48 << MCDE_OVLXCONF2_PIXELFETCHERWATERMARKLEVEL_SHIFT;
> +
> + /*
> + * Pixel fetch watermark level is max 0x1FFF pixels.
> + * Two basic rules should be followed:
> + * 1. The value should be at least 256 bits.
> + * 2. The sum of all active overlays pixelfetch watermark level
> + * multiplied with bits per pixel, should be lower than the
> + * size of input_fifo_size in bits.
> + * 3. The value should be a multiple of a line (256 bits).
> + */
> + switch (cpp) {
> + case 2:
> + pixel_fetcher_watermark = 128;
> + break;
> + case 3:
> + pixel_fetcher_watermark = 96;
> + break;
> + case 4:
> + pixel_fetcher_watermark = 48;
> + break;
> + default:
> + pixel_fetcher_watermark = 48;
> + break;
> + }
> + dev_dbg(mcde->dev, "pixel fetcher watermark level %d pixels\n",
> + pixel_fetcher_watermark);
> + val |= pixel_fetcher_watermark << MCDE_OVLXCONF2_PIXELFETCHERWATERMARKLEVEL_SHIFT;
> writel(val, mcde->regs + conf2);
>
> /* Number of bytes to fetch per line */
> @@ -932,7 +958,7 @@ static void mcde_display_enable(struct drm_simple_display_pipe *pipe,
> * channel 0
> */
> mcde_configure_overlay(mcde, MCDE_OVERLAY_0, MCDE_EXTSRC_0,
> - MCDE_CHANNEL_0, mode, format);
> + MCDE_CHANNEL_0, mode, format, cpp);
>
> /*
> * Configure pixel-per-line and line-per-frame for channel 0 and then
> --
> 2.26.2
>
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> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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