Hi Hsia-Jun,
Thank you for the patch.
On Tue, Aug 09, 2022 at 12:27:49AM +0800, Hsia-Jun Li wrote:
> From: "Hsia-Jun(Randy) Li" <randy.li@xxxxxxxxxxxxx>
>
> Memory Traffic Reduction(MTR) is a module in Synaptics
> VideoSmart platform could process lossless compression image
> and cache the tile memory line.
>
> Those modifiers only record the parameters would effort pixel
> layout or memory layout. Whether physical memory page mapping
> is used is not a part of format.
>
> We would allocate the same size of memory for uncompressed
> and compressed luma and chroma data, while the compressed buffer
> would request two extra planes holding the metadata for
> the decompression.
>
> The reason why we need to allocate the same size of memory for
> the compressed frame:
> 1. The compression ratio is not fixed and differnt platforms could
> use a different compression protocol. These protocols are complete
> vendor proprietaries, the other device won't be able to use them.
> It is not necessary to define the version of them here.
>
> 2. Video codec could discard the compression attribute when the
> intra block copy applied to this frame. It would waste lots of
> time on re-allocation.
>
> I am wondering if it is better to add an addtional plane property to
> describe whether the current framebuffer is compressed?
> While the compression flag is still a part of format modifier,
> because it would have two extra meta data planes in the compression
> version.
Would it possible to show an example of how these modifiers apply to a
particular format (such as NV12 for instance) ? Otherwise I'm having
trouble understanding how they actually work.
> Signed-off-by: Hsia-Jun(Randy) Li <randy.li@xxxxxxxxxxxxx>
> ---
> include/uapi/drm/drm_fourcc.h | 49 +++++++++++++++++++++++++++++++++++
> 1 file changed, 49 insertions(+)
>
> diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h
> index 0206f812c569..b67884e8bc69 100644
> --- a/include/uapi/drm/drm_fourcc.h
> +++ b/include/uapi/drm/drm_fourcc.h
> @@ -381,6 +381,7 @@ extern "C" {
> #define DRM_FORMAT_MOD_VENDOR_ARM 0x08
> #define DRM_FORMAT_MOD_VENDOR_ALLWINNER 0x09
> #define DRM_FORMAT_MOD_VENDOR_AMLOGIC 0x0a
> +#define DRM_FORMAT_MOD_VENDOR_SYNAPTICS 0x0b
>
> /* add more to the end as needed */
>
> @@ -1452,6 +1453,54 @@ drm_fourcc_canonicalize_nvidia_format_mod(__u64 modifier)
> #define AMD_FMT_MOD_CLEAR(field) \
> (~((__u64)AMD_FMT_MOD_##field##_MASK << AMD_FMT_MOD_##field##_SHIFT))
>
> +/*
> + * Synaptics VideoSmart modifiers
> + *
> + * Macro
> + * Bits Param Description
> + * ---- ----- -----------------------------------------------------------------
> + *
> + * 7:0 f Scan direction description.
> + *
> + * 0 = Invalid
> + * 1 = V4, the scan would always start from vertical for 4 pixel
> + * then move back to the start pixel of the next horizontal
> + * direction.
> + * 2 = Reserved for future use.
> + *
> + * 15:8 m The times of pattern repeat in the right angle direction from
> + * the first scan direction.
> + *
> + * 19:16 p The padding bits after the whole scan, could be zero.
> + *
> + * 35:20 - Reserved for future use. Must be zero.
> + *
> + * 36:36 c Compression flag.
> + *
> + * 55:37 - Reserved for future use. Must be zero.
> + *
> + */
> +
> +#define DRM_FORMAT_MOD_SYNA_V4_TILED fourcc_mod_code(SYNAPTICS, 1)
> +
> +#define DRM_FORMAT_MOD_SYNA_MTR_LINEAR_2D(f, m, p, c) \
> + fourcc_mod_code(SYNAPTICS, (((f) & 0xff) | \
> + (((m) & 0xff) << 8) | \
> + (((p) & 0xf) << 16) | \
> + (((c) & 0x1) << 36)))
> +
> +#define DRM_FORMAT_MOD_SYNA_V4H1 \
> + DRM_FORMAT_MOD_SYNA_MTR_LINEAR_2D(1, 1, 0, 0)
> +
> +#define DRM_FORMAT_MOD_SYNA_V4H3P8 \
> + DRM_FORMAT_MOD_SYNA_MTR_LINEAR_2D(1, 3, 8, 0)
> +
> +#define DRM_FORMAT_MOD_SYNA_V4H1_COMPRESSED \
> + DRM_FORMAT_MOD_SYNA_MTR_LINEAR_2D(1, 1, 0, 1)
> +
> +#define DRM_FORMAT_MOD_SYNA_V4H3P8_COMPRESSED \
> + DRM_FORMAT_MOD_SYNA_MTR_LINEAR_2D(1, 3, 8, 1)
> +
> #if defined(__cplusplus)
> }
> #endif
--
Regards,
Laurent Pinchart
