On 2022-02-17 15:28, Pekka Paalanen wrote:
On Thu, 17 Feb 2022 11:42:29 +0100 Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:Hi Pekka, On Thu, Feb 17, 2022 at 11:10 AM Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote:On Tue, 15 Feb 2022 17:52:26 +0100 Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:Introduce a fourcc code for a single-channel frame buffer format with two darkness levels. This can be used for two-level dark-on-light displays. As the number of bits per pixel is less than eight, this relies on proper block handling for the calculation of bits per pixel and pitch. Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>--- a/drivers/gpu/drm/drm_fourcc.c +++ b/drivers/gpu/drm/drm_fourcc.c @@ -151,6 +151,8 @@ const struct drm_format_info *__drm_format_info(u32 format) { .format = DRM_FORMAT_C4, .depth = 4, .num_planes = 1, .char_per_block = { 1, }, .block_w = { 2, }, .block_h = { 1, }, .hsub = 1, .vsub = 1 }, { .format = DRM_FORMAT_C8, .depth = 8, .num_planes = 1, .cpp = { 1, 0, 0 }, .hsub = 1, .vsub = 1 }, + { .format = DRM_FORMAT_D1, .depth = 1, .num_planes = 1, + .char_per_block = { 1, }, .block_w = { 8, }, .block_h = { 1, }, .hsub = 1, .vsub = 1 }, { .format = DRM_FORMAT_R1, .depth = 1, .num_planes = 1, .char_per_block = { 1, }, .block_w = { 8, }, .block_h = { 1, }, .hsub = 1, .vsub = 1 }, { .format = DRM_FORMAT_R2, .depth = 2, .num_planes = 1, diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h index 8605a1acc6813e6c..c15c6efcc65e5827 100644 --- a/include/uapi/drm/drm_fourcc.h +++ b/include/uapi/drm/drm_fourcc.h @@ -104,6 +104,9 @@ extern "C" { #define DRM_FORMAT_C4 fourcc_code('C', '4', ' ', ' ') /* [3:0] C */ #define DRM_FORMAT_C8 fourcc_code('C', '8', ' ', ' ') /* [7:0] C */ +/* 1 bpp Darkness */ +#define DRM_FORMAT_D1 fourcc_code('D', '1', ' ', ' ') /* [0] D */ +the same comment here as for C1 and R1 formats, need to specify pixel ordering inside a byte.Right, will do.Btw. does endianess of anything have any effect on these pixel formats? That's probably a weird question, but I recall Pixman (the pixel handling library of the X server nowadays known as Xorg) having pixel formats where CPU endianess affects whether the first pixel in a byte is found at the MSB or LSB.
Pixman probably has that for hysterical raisins inherited from the X code base. Conceptually, endianness is purely about the order of bytes in words, and is orthogonal to the order in which the bits of a byte/word are numbered. -- Earthling Michel Dänzer | https://redhat.com Libre software enthusiast | Mesa and Xwayland developer
