@@ -178,6 +178,24 @@ static enum pixel_read_direction direction_for_rotation(unsigned int rotation)
return READ_LEFT_TO_RIGHT;
}
+/**
+ * Write a line to the writeback buffer
+ *
+ * @wb: Job where to insert the final image
+ * @src_buffer: Line to write
+ * @y: Row to write in the writeback buffer
+ */
+static void vkms_writeback_row(struct vkms_writeback_job *wb,
+ const struct line_buffer *src_buffer, size_t y_start)
+{
+ struct vkms_frame_info *frame_info = &wb->wb_frame_info;
+ int x_start = frame_info->dst.x1;
+ int count = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
+
+ wb->pixel_write(wb, src_buffer->pixels, count, x_start, y_start);
+}
+
+
/**
* clamp_line_coordinates() - Compute and clamp the coordinate to read and write during the blend
* process.
@@ -52,20 +52,25 @@ struct line_buffer {
struct pixel_argb_u16 *pixels;
};
+struct vkms_writeback_job;
/**
- * typedef pixel_write_t - These functions are used to read a pixel from a
- * &struct pixel_argb_u16, convert it in a specific format and write it in the @dst_pixels
- * buffer.
+ * typedef pixel_write_line_t - These functions are used to read a pixel line from a
+ * struct pixel_argb_u16 buffer, convert it and write it in the @wb job.
*
- * @out_pixel: destination address to write the pixel
- * @in_pixel: pixel to write
+ * @wb: the writeback job to write the output of the conversion
+ * @in_pixels: Source buffer containing the line to convert
+ * @count: The width of a line
+ * @x_start: The x (width) coordinate in the destination plane
+ * @y_start: The y (height) coordinate in the destination plane
*/
-typedef void (*pixel_write_t)(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel);
+typedef void (*pixel_write_line_t)(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *in_pixels, int count, int x_start,
+ int y_start);
struct vkms_writeback_job {
struct iosys_map data[DRM_FORMAT_MAX_PLANES];
struct vkms_frame_info wb_frame_info;
- pixel_write_t pixel_write;
+ pixel_write_line_t pixel_write;
};
/**
@@ -233,7 +238,6 @@ int vkms_verify_crc_source(struct drm_crtc *crtc, const char *source_name,
/* Composer Support */
void vkms_composer_worker(struct work_struct *work);
void vkms_set_composer(struct vkms_output *out, bool enabled);
-void vkms_writeback_row(struct vkms_writeback_job *wb, const struct line_buffer *src_buffer, int y);
/* Writeback */
int vkms_enable_writeback_connector(struct vkms_device *vkmsdev);
@@ -575,7 +575,7 @@ static void planar_yuv_read_line(const struct vkms_plane_state *plane, int x_sta
* The following functions take one &struct pixel_argb_u16 and convert it to a specific format.
* The result is stored in @out_pixel.
*
- * They are used in vkms_writeback_row() to convert and store a pixel from the src_buffer to
+ * They are used in the `write_line` functions to convert and store a pixel from the src_buffer to
* the writeback buffer.
*/
static void argb_u16_to_ARGB8888(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
@@ -642,40 +642,111 @@ static void argb_u16_to_RGB565(u8 *out_pixel, const struct pixel_argb_u16 *in_pi
*pixel = cpu_to_le16(r << 11 | g << 5 | b);
}
-/**
- * argb_u16_to_nothing() - pixel_write callback with no effect
+/*
+ * The following functions are write_line function for each pixel format supported by VKMS.
*
- * This callback is used when an invalid format is requested for writeback.
- * It is used to avoid null pointer to be used as a function. In theory, this should never
- * happen, except if there is a bug in the driver
- */
-static void argb_u16_to_nothing(u8 *out_pixel, const struct pixel_argb_u16 *in_pixel)
-{}
-
-/**
- * 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.
+ * They write a full line at index y. They must read data from the line src_pixels.
+ *
+ * The caller must ensure that count is not larger than the framebuffer and the src_pixels.
*
- * @wb: Job where to insert the final image
- * @src_buffer: Line to write
- * @y: Row to write in the writeback buffer
+ * Those function are very similar, but it is required for performance reason. In the past, some
+ * experiment were done, and with a generic loop the performance are very reduced [1].
+ *
+ * [1]: https://lore.kernel.org/dri-devel/d258c8dc-78e9-4509-9037-a98f7f33b3a3@riseup.net/
*/
-void vkms_writeback_row(struct vkms_writeback_job *wb,
- const struct line_buffer *src_buffer, int y)
+
+static void ARGB8888_write_line(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *src_pixels, int count, int x_start,
+ int y_start)
{
- struct vkms_frame_info *frame_info = &wb->wb_frame_info;
- int x_dst = frame_info->dst.x1;
u8 *dst_pixels;
- int rem_x, rem_y;
- packed_pixels_addr(frame_info, x_dst, y, 0, &dst_pixels, &rem_x, &rem_y);
- struct pixel_argb_u16 *in_pixels = src_buffer->pixels;
- int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst), src_buffer->n_pixels);
+ packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
- for (size_t x = 0; x < x_limit; x++, dst_pixels += frame_info->fb->format->cpp[0])
- wb->pixel_write(dst_pixels, &in_pixels[x]);
+ while (count) {
+ argb_u16_to_ARGB8888(dst_pixels, src_pixels);
+ dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
+ src_pixels += 1;
+ count--;
+ }
}
+static void XRGB8888_write_line(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *src_pixels, int count, int x_start,
+ int y_start)
+{
+ u8 *dst_pixels;
+
+ packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
+
+ while (count) {
+ argb_u16_to_XRGB8888(dst_pixels, src_pixels);
+ dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
+ src_pixels += 1;
+ count--;
+ }
+}
+
+static void ARGB16161616_write_line(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *src_pixels, int count, int x_start,
+ int y_start)
+{
+ u8 *dst_pixels;
+
+ packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
+
+ while (count) {
+ argb_u16_to_ARGB16161616(dst_pixels, src_pixels);
+ dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
+ src_pixels += 1;
+ count--;
+ }
+}
+
+static void XRGB16161616_write_line(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *src_pixels, int count, int x_start,
+ int y_start)
+{
+ u8 *dst_pixels;
+
+ packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
+
+ while (count) {
+ argb_u16_to_XRGB16161616(dst_pixels, src_pixels);
+ dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
+ src_pixels += 1;
+ count--;
+ }
+}
+
+static void RGB565_write_line(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *src_pixels, int count, int x_start,
+ int y_start)
+{
+ u8 *dst_pixels;
+
+ packed_pixels_addr_1x1(&wb->wb_frame_info, x_start, y_start, 0, &dst_pixels);
+
+ while (count) {
+ argb_u16_to_RGB565(dst_pixels, src_pixels);
+ dst_pixels += wb->wb_frame_info.fb->format->char_per_block[0];
+ src_pixels += 1;
+ count--;
+ }
+}
+
+/**
+ * argb_u16_to_nothing() - pixel_write callback with no effect
+ *
+ * This callback is used when an invalid format is requested for writeback.
+ * It is used to avoid null pointer to be used as a function. In theory, this should never
+ * happen, except if there is a bug in the driver
+ */
+static void nothing_write_line(struct vkms_writeback_job *wb,
+ struct pixel_argb_u16 *src_pixels, int count, int x_start,
+ int y_start)
+{}
+
/**
* get_pixel_read_function() - Retrieve the correct read_line function for a specific
* format.
@@ -936,25 +1007,25 @@ void get_conversion_matrix_to_argb_u16(u32 format,
}
/**
- * get_pixel_write_function() - Retrieve the correct write_pixel function for a specific format.
+ * get_pixel_write_function() - Retrieve the correct write_line function for a specific format.
* If the format is not supported by VKMS a warning is emitted and a dummy "don't do anything"
* function is returned.
*
* @format: DRM_FORMAT_* value for which to obtain a conversion function (see [drm_fourcc.h])
*/
-pixel_write_t get_pixel_write_function(u32 format)
+pixel_write_line_t get_pixel_write_line_function(u32 format)
{
switch (format) {
case DRM_FORMAT_ARGB8888:
- return &argb_u16_to_ARGB8888;
+ return &ARGB8888_write_line;
case DRM_FORMAT_XRGB8888:
- return &argb_u16_to_XRGB8888;
+ return &XRGB8888_write_line;
case DRM_FORMAT_ARGB16161616:
- return &argb_u16_to_ARGB16161616;
+ return &ARGB16161616_write_line;
case DRM_FORMAT_XRGB16161616:
- return &argb_u16_to_XRGB16161616;
+ return &XRGB16161616_write_line;
case DRM_FORMAT_RGB565:
- return &argb_u16_to_RGB565;
+ return &RGB565_write_line;
default:
/*
* This is a bug in vkms_writeback_atomic_check. All the supported
@@ -968,6 +1039,6 @@ pixel_write_t get_pixel_write_function(u32 format)
WARN(true,
"Pixel format %p4cc is not supported by VKMS writeback. This is a kernel bug, atomic check must forbid this configuration.\n",
&format);
- return &argb_u16_to_nothing;
+ return ¬hing_write_line;
}
}
@@ -7,7 +7,7 @@
pixel_read_line_t get_pixel_read_line_function(u32 format);
-pixel_write_t get_pixel_write_function(u32 format);
+pixel_write_line_t get_pixel_write_line_function(u32 format);
void get_conversion_matrix_to_argb_u16(u32 format, enum drm_color_encoding encoding,
enum drm_color_range range,
@@ -150,7 +150,7 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn,
crtc_state->wb_pending = true;
spin_unlock_irq(&output->composer_lock);
drm_writeback_queue_job(wb_conn, connector_state);
- active_wb->pixel_write = get_pixel_write_function(wb_format);
+ active_wb->pixel_write = get_pixel_write_line_function(wb_format);
drm_rect_init(&wb_frame_info->src, 0, 0, crtc_width, crtc_height);
drm_rect_init(&wb_frame_info->dst, 0, 0, crtc_width, crtc_height);
}
Re-introduce a line-by-line writeback algorithm for each pixel format. This allows more performance by not requiring an indirection per pixel write. Line-by-line writeback was introduced by [1] but rewritten back to pixel-by-pixel algorithm in [2]. At this time, nobody noticed the impact on performance, and it was merged. This patch is almost a revert of [2], but with some effort to avoid code duplication. Now only the loop is repeated, but it is required to have good performances. The performance gain is around 5 to 10%. [1]: https://lore.kernel.org/all/20211005201637.58563-7-igormtorrente@gmail.com/ [2]: https://lore.kernel.org/all/20230515135204.115393-4-mcanal@igalia.com/ Signed-off-by: Louis Chauvet <louis.chauvet@bootlin.com> --- drivers/gpu/drm/vkms/vkms_composer.c | 18 +++++ drivers/gpu/drm/vkms/vkms_drv.h | 20 +++-- drivers/gpu/drm/vkms/vkms_formats.c | 139 +++++++++++++++++++++++++--------- drivers/gpu/drm/vkms/vkms_formats.h | 2 +- drivers/gpu/drm/vkms/vkms_writeback.c | 2 +- 5 files changed, 137 insertions(+), 44 deletions(-)