| Message ID | 20240409-yuv-v6-3-de1c5728fd70@bootlin.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/vkms: Reimplement line-per-line pixel conversion for plane reading | expand |
On Tue, 09 Apr 2024 15:25:21 +0200 Louis Chauvet <louis.chauvet@bootlin.com> wrote: > Add some documentation on pixel conversion functions. > Update of outdated comments for pixel_write functions. > > Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com> > --- > drivers/gpu/drm/vkms/vkms_composer.c | 7 ++++ > drivers/gpu/drm/vkms/vkms_drv.h | 15 ++++++++- > drivers/gpu/drm/vkms/vkms_formats.c | 62 ++++++++++++++++++++++++++++++------ > 3 files changed, 74 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c > index c6d9b4a65809..da0651a94c9b 100644 > --- a/drivers/gpu/drm/vkms/vkms_composer.c > +++ b/drivers/gpu/drm/vkms/vkms_composer.c > @@ -189,6 +189,13 @@ static void blend(struct vkms_writeback_job *wb, > > size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay; > > + /* > + * The planes are composed line-by-line to avoid heavy memory usage. It is a necessary > + * complexity to avoid poor blending performance. > + * > + * The function vkms_compose_row is used to read a line, pixel-by-pixel, into the staging > + * buffer. > + */ > for (size_t y = 0; y < crtc_y_limit; y++) { > fill_background(&background_color, output_buffer); > > diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h > index b4b357447292..a86cb537d6aa 100644 > --- a/drivers/gpu/drm/vkms/vkms_drv.h > +++ b/drivers/gpu/drm/vkms/vkms_drv.h > @@ -25,6 +25,17 @@ > > #define VKMS_LUT_SIZE 256 > > +/** > + * struct vkms_frame_info - structure to store the state of a frame > + * > + * @fb: backing drm framebuffer > + * @src: source rectangle of this frame in the source framebuffer > + * @dst: destination rectangle in the crtc buffer Are both src and dst using whole pixel units, or is src using 1/65536th pixel units? Asking because UAPI has src rect in 16.16 fixed-point, IIRC. With that clarified: Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com> Thanks, pq > + * @map: see drm_shadow_plane_state@data > + * @rotation: rotation applied to the source. > + * > + * @src and @dst should have the same size modulo the rotation. > + */ > struct vkms_frame_info { > struct drm_framebuffer *fb; > struct drm_rect src, dst; > @@ -49,9 +60,11 @@ struct vkms_writeback_job { > }; > > /** > - * vkms_plane_state - Driver specific plane state > + * struct vkms_plane_state - Driver specific plane state > * @base: base plane state > * @frame_info: data required for composing computation > + * @pixel_read: function to read a pixel in this plane. The creator of a vkms_plane_state must > + * ensure that this pointer is valid > */ > struct vkms_plane_state { > struct drm_shadow_plane_state base; > diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c > index d597c48452ac..f157c43da4d6 100644 > --- a/drivers/gpu/drm/vkms/vkms_formats.c > +++ b/drivers/gpu/drm/vkms/vkms_formats.c > @@ -9,6 +9,18 @@ > > #include "vkms_formats.h" > > +/** > + * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane > + * > + * @frame_info: Buffer metadata > + * @x: The x coordinate of the wanted pixel in the buffer > + * @y: The y coordinate of the wanted pixel in the buffer > + * > + * The caller must ensure that the framebuffer associated with this request uses a pixel format > + * where block_h == block_w == 1. > + * If this requirement is not fulfilled, the resulting offset can point to an other pixel or > + * outside of the buffer. > + */ > static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y) > { > struct drm_framebuffer *fb = frame_info->fb; > @@ -16,18 +28,22 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int > return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]); > } > > -/* > - * packed_pixels_addr - Get the pointer to pixel of a given pair of coordinates > +/** > + * packed_pixels_addr() - Get the pointer to the block containing the pixel at the given > + * coordinates > * > * @frame_info: Buffer metadata > - * @x: The x(width) coordinate of the 2D buffer > - * @y: The y(Heigth) coordinate of the 2D buffer > + * @x: The x (width) coordinate inside the plane > + * @y: The y (height) coordinate inside the plane > * > * Takes the information stored in the frame_info, a pair of coordinates, and > * returns the address of the first color channel. > * This function assumes the channels are packed together, i.e. a color channel > * comes immediately after another in the memory. And therefore, this function > * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21). > + * > + * The caller must ensure that the framebuffer associated with this request uses a pixel format > + * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer. > */ > static void *packed_pixels_addr(const struct vkms_frame_info *frame_info, > int x, int y) > @@ -52,6 +68,13 @@ static int get_x_position(const struct vkms_frame_info *frame_info, int limit, i > return x; > } > > +/* > + * The following functions take pixel data from the buffer and convert them to the format > + * ARGB16161616 in out_pixel. > + * > + * They are used in the vkms_compose_row() function to handle multiple formats. > + */ > + > static void ARGB8888_to_argb_u16(u8 *src_pixels, struct pixel_argb_u16 *out_pixel) > { > /* > @@ -144,12 +167,11 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state > } > > /* > - * The following functions take an line of argb_u16 pixels from the > - * src_buffer, convert them to a specific format, and store them in the > - * destination. > + * The following functions take one &struct pixel_argb_u16 and convert it to a specific format. > + * The result is stored in @dst_pixels. > * > - * They are used in the `compose_active_planes` to convert and store a line > - * from the src_buffer to the writeback buffer. > + * They are used in vkms_writeback_row() to convert and store a pixel from the src_buffer to > + * the writeback buffer. > */ > static void argb_u16_to_ARGB8888(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel) > { > @@ -215,6 +237,14 @@ static void argb_u16_to_RGB565(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel) > *pixels = cpu_to_le16(r << 11 | g << 5 | b); > } > > +/** > + * vkms_writeback_row() - Generic loop for all supported writeback format. It is executed just > + * after the blending to write a line in the writeback buffer. > + * > + * @wb: Job where to insert the final image > + * @src_buffer: Line to write > + * @y: Row to write in the writeback buffer > + */ > void vkms_writeback_row(struct vkms_writeback_job *wb, > const struct line_buffer *src_buffer, int y) > { > @@ -228,6 +258,13 @@ void vkms_writeback_row(struct vkms_writeback_job *wb, > wb->pixel_write(dst_pixels, &in_pixels[x]); > } > > +/** > + * get_pixel_conversion_function() - Retrieve the correct read_pixel function for a specific > + * format. The returned pointer is NULL for unsupported pixel formats. The caller must ensure that > + * the pointer is valid before using it in a vkms_plane_state. > + * > + * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h]) > + */ > void *get_pixel_conversion_function(u32 format) > { > switch (format) { > @@ -246,6 +283,13 @@ void *get_pixel_conversion_function(u32 format) > } > } > > +/** > + * get_pixel_write_function() - Retrieve the correct write_pixel function for a specific format. > + * The returned pointer is NULL for unsupported pixel formats. The caller must ensure that the > + * pointer is valid before using it in a vkms_writeback_job. > + * > + * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h]) > + */ > void *get_pixel_write_function(u32 format) > { > switch (format) { >
diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c index c6d9b4a65809..da0651a94c9b 100644 --- a/drivers/gpu/drm/vkms/vkms_composer.c +++ b/drivers/gpu/drm/vkms/vkms_composer.c @@ -189,6 +189,13 @@ static void blend(struct vkms_writeback_job *wb, size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay; + /* + * The planes are composed line-by-line to avoid heavy memory usage. It is a necessary + * complexity to avoid poor blending performance. + * + * The function vkms_compose_row is used to read a line, pixel-by-pixel, into the staging + * buffer. + */ for (size_t y = 0; y < crtc_y_limit; y++) { fill_background(&background_color, output_buffer); diff --git a/drivers/gpu/drm/vkms/vkms_drv.h b/drivers/gpu/drm/vkms/vkms_drv.h index b4b357447292..a86cb537d6aa 100644 --- a/drivers/gpu/drm/vkms/vkms_drv.h +++ b/drivers/gpu/drm/vkms/vkms_drv.h @@ -25,6 +25,17 @@ #define VKMS_LUT_SIZE 256 +/** + * struct vkms_frame_info - structure to store the state of a frame + * + * @fb: backing drm framebuffer + * @src: source rectangle of this frame in the source framebuffer + * @dst: destination rectangle in the crtc buffer + * @map: see drm_shadow_plane_state@data + * @rotation: rotation applied to the source. + * + * @src and @dst should have the same size modulo the rotation. + */ struct vkms_frame_info { struct drm_framebuffer *fb; struct drm_rect src, dst; @@ -49,9 +60,11 @@ struct vkms_writeback_job { }; /** - * vkms_plane_state - Driver specific plane state + * struct vkms_plane_state - Driver specific plane state * @base: base plane state * @frame_info: data required for composing computation + * @pixel_read: function to read a pixel in this plane. The creator of a vkms_plane_state must + * ensure that this pointer is valid */ struct vkms_plane_state { struct drm_shadow_plane_state base; diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c index d597c48452ac..f157c43da4d6 100644 --- a/drivers/gpu/drm/vkms/vkms_formats.c +++ b/drivers/gpu/drm/vkms/vkms_formats.c @@ -9,6 +9,18 @@ #include "vkms_formats.h" +/** + * pixel_offset() - Get the offset of the pixel at coordinates x/y in the first plane + * + * @frame_info: Buffer metadata + * @x: The x coordinate of the wanted pixel in the buffer + * @y: The y coordinate of the wanted pixel in the buffer + * + * The caller must ensure that the framebuffer associated with this request uses a pixel format + * where block_h == block_w == 1. + * If this requirement is not fulfilled, the resulting offset can point to an other pixel or + * outside of the buffer. + */ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y) { struct drm_framebuffer *fb = frame_info->fb; @@ -16,18 +28,22 @@ static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int return fb->offsets[0] + (y * fb->pitches[0]) + (x * fb->format->cpp[0]); } -/* - * packed_pixels_addr - Get the pointer to pixel of a given pair of coordinates +/** + * packed_pixels_addr() - Get the pointer to the block containing the pixel at the given + * coordinates * * @frame_info: Buffer metadata - * @x: The x(width) coordinate of the 2D buffer - * @y: The y(Heigth) coordinate of the 2D buffer + * @x: The x (width) coordinate inside the plane + * @y: The y (height) coordinate inside the plane * * Takes the information stored in the frame_info, a pair of coordinates, and * returns the address of the first color channel. * This function assumes the channels are packed together, i.e. a color channel * comes immediately after another in the memory. And therefore, this function * doesn't work for YUV with chroma subsampling (e.g. YUV420 and NV21). + * + * The caller must ensure that the framebuffer associated with this request uses a pixel format + * where block_h == block_w == 1, otherwise the returned pointer can be outside the buffer. */ static void *packed_pixels_addr(const struct vkms_frame_info *frame_info, int x, int y) @@ -52,6 +68,13 @@ static int get_x_position(const struct vkms_frame_info *frame_info, int limit, i return x; } +/* + * The following functions take pixel data from the buffer and convert them to the format + * ARGB16161616 in out_pixel. + * + * They are used in the vkms_compose_row() function to handle multiple formats. + */ + static void ARGB8888_to_argb_u16(u8 *src_pixels, struct pixel_argb_u16 *out_pixel) { /* @@ -144,12 +167,11 @@ void vkms_compose_row(struct line_buffer *stage_buffer, struct vkms_plane_state } /* - * The following functions take an line of argb_u16 pixels from the - * src_buffer, convert them to a specific format, and store them in the - * destination. + * The following functions take one &struct pixel_argb_u16 and convert it to a specific format. + * The result is stored in @dst_pixels. * - * They are used in the `compose_active_planes` to convert and store a line - * from the src_buffer to the writeback buffer. + * They are used in vkms_writeback_row() to convert and store a pixel from the src_buffer to + * the writeback buffer. */ static void argb_u16_to_ARGB8888(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel) { @@ -215,6 +237,14 @@ static void argb_u16_to_RGB565(u8 *dst_pixels, struct pixel_argb_u16 *in_pixel) *pixels = cpu_to_le16(r << 11 | g << 5 | b); } +/** + * vkms_writeback_row() - Generic loop for all supported writeback format. It is executed just + * after the blending to write a line in the writeback buffer. + * + * @wb: Job where to insert the final image + * @src_buffer: Line to write + * @y: Row to write in the writeback buffer + */ void vkms_writeback_row(struct vkms_writeback_job *wb, const struct line_buffer *src_buffer, int y) { @@ -228,6 +258,13 @@ void vkms_writeback_row(struct vkms_writeback_job *wb, wb->pixel_write(dst_pixels, &in_pixels[x]); } +/** + * get_pixel_conversion_function() - Retrieve the correct read_pixel function for a specific + * format. The returned pointer is NULL for unsupported pixel formats. The caller must ensure that + * the pointer is valid before using it in a vkms_plane_state. + * + * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h]) + */ void *get_pixel_conversion_function(u32 format) { switch (format) { @@ -246,6 +283,13 @@ void *get_pixel_conversion_function(u32 format) } } +/** + * get_pixel_write_function() - Retrieve the correct write_pixel function for a specific format. + * The returned pointer is NULL for unsupported pixel formats. The caller must ensure that the + * pointer is valid before using it in a vkms_writeback_job. + * + * @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h]) + */ void *get_pixel_write_function(u32 format) { switch (format) {
Add some documentation on pixel conversion functions. Update of outdated comments for pixel_write functions. Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com> --- drivers/gpu/drm/vkms/vkms_composer.c | 7 ++++ drivers/gpu/drm/vkms/vkms_drv.h | 15 ++++++++- drivers/gpu/drm/vkms/vkms_formats.c | 62 ++++++++++++++++++++++++++++++------ 3 files changed, 74 insertions(+), 10 deletions(-)