[RESEND v6 6/9] drm: vkms: Refactor the plane composer to accept new formats
Igor Matheus Andrade Torrente
igormtorrente at gmail.com
Mon Aug 22 18:27:36 UTC 2022
Hi Melissa,
On 8/20/22 07:51, Melissa Wen wrote:
> On 08/19, Igor Torrente wrote:
>> Currently the blend function only accepts XRGB_8888 and ARGB_8888
>> as a color input.
>>
>> This patch refactors all the functions related to the plane composition
>> to overcome this limitation.
>>
>> The pixels blend is done using the new internal format. And new handlers
>> are being added to convert a specific format to/from this internal format.
>>
>> So the blend operation depends on these handlers to convert to this common
>> format. The blended result, if necessary, is converted to the writeback
>> buffer format.
>>
>> This patch introduces three major differences to the blend function.
>> 1 - All the planes are blended at once.
>> 2 - The blend calculus is done as per line instead of per pixel.
>> 3 - It is responsible to calculates the CRC and writing the writeback
>> buffer(if necessary).
>>
>> These changes allow us to allocate way less memory in the intermediate
>> buffer to compute these operations. Because now we don't need to
>> have the entire intermediate image lines at once, just one line is
>> enough.
>>
>> | Memory consumption (output dimensions) |
>> |:--------------------------------------:|
>> | Current | This patch |
>> |:------------------:|:-----------------:|
>> | Width * Heigth | 2 * Width |
>>
>> Beyond memory, we also have a minor performance benefit from all
>> these changes. Results running the IGT[1] test
>> `igt at kms_cursor_crc@pipe-a-cursor-512x512-onscreen` ten times:
>>
>> | Frametime |
>> |:------------------------------------------:|
>> | Implementation | Current | This commit |
>> |:---------------:|:---------:|:------------:|
>> | frametime range | 9~22 ms | 5~17 ms |
>> | Average | 11.4 ms | 7.8 ms |
>>
>> [1] IGT commit id: bc3f6833a12221a46659535dac06ebb312490eb4
>>
>> V2: Improves the performance drastically, by performing the operations
>> per-line and not per-pixel(Pekka Paalanen).
>> Minor improvements(Pekka Paalanen).
>> V3: Changes the code to blend the planes all at once. This improves
>> performance, memory consumption, and removes much of the weirdness
>> of the V2(Pekka Paalanen and me).
>> Minor improvements(Pekka Paalanen and me).
>> V4: Rebase the code and adapt it to the new NUM_OVERLAY_PLANES constant.
>> V5: Minor checkpatch fixes and the removal of TO-DO item(Melissa Wen).
>> Several security/robustness improvents(Pekka Paalanen).
>> Removes check_planes_x_bounds function and allows partial
>> partly off-screen(Pekka Paalanen).
>> V6: Fix a mismatch of some variable sizes (Pekka Paalanen).
>> Several minor improvements (Pekka Paalanen).
>>
>> Reported-by: kernel test robot <lkp at intel.com>
>> Signed-off-by: Igor Torrente <igormtorrente at gmail.com>
>> ---
>> Documentation/gpu/vkms.rst | 4 -
>> drivers/gpu/drm/vkms/Makefile | 1 +
>> drivers/gpu/drm/vkms/vkms_composer.c | 320 ++++++++++++--------------
>> drivers/gpu/drm/vkms/vkms_formats.c | 155 +++++++++++++
>> drivers/gpu/drm/vkms/vkms_formats.h | 12 +
>> drivers/gpu/drm/vkms/vkms_plane.c | 3 +
>> drivers/gpu/drm/vkms/vkms_writeback.c | 3 +
>> 7 files changed, 317 insertions(+), 181 deletions(-)
>> create mode 100644 drivers/gpu/drm/vkms/vkms_formats.c
>> create mode 100644 drivers/gpu/drm/vkms/vkms_formats.h
>>
>> diff --git a/Documentation/gpu/vkms.rst b/Documentation/gpu/vkms.rst
>> index 973e2d43108b..a49e4ae92653 100644
>> --- a/Documentation/gpu/vkms.rst
>> +++ b/Documentation/gpu/vkms.rst
>> @@ -118,10 +118,6 @@ Add Plane Features
>>
>> There's lots of plane features we could add support for:
>>
>> -- Clearing primary plane: clear primary plane before plane composition (at the
>> - start) for correctness of pixel blend ops. It also guarantees alpha channel
>> - is cleared in the target buffer for stable crc. [Good to get started]
>> -
>> - ARGB format on primary plane: blend the primary plane into background with
>> translucent alpha.
>>
>> diff --git a/drivers/gpu/drm/vkms/Makefile b/drivers/gpu/drm/vkms/Makefile
>> index 72f779cbfedd..1b28a6a32948 100644
>> --- a/drivers/gpu/drm/vkms/Makefile
>> +++ b/drivers/gpu/drm/vkms/Makefile
>> @@ -3,6 +3,7 @@ vkms-y := \
>> vkms_drv.o \
>> vkms_plane.o \
>> vkms_output.o \
>> + vkms_formats.o \
>> vkms_crtc.o \
>> vkms_composer.o \
>> vkms_writeback.o
>> diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c
>> index b9fb408e8973..5b1a8bdd8268 100644
>> --- a/drivers/gpu/drm/vkms/vkms_composer.c
>> +++ b/drivers/gpu/drm/vkms/vkms_composer.c
>> @@ -7,204 +7,188 @@
>> #include <drm/drm_fourcc.h>
>> #include <drm/drm_gem_framebuffer_helper.h>
>> #include <drm/drm_vblank.h>
>> +#include <linux/minmax.h>
>>
>> #include "vkms_drv.h"
>>
>> -static u32 get_pixel_from_buffer(int x, int y, const u8 *buffer,
>> - const struct vkms_frame_info *frame_info)
>> +static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha)
>> {
>> - u32 pixel;
>> - int src_offset = frame_info->offset + (y * frame_info->pitch)
>> - + (x * frame_info->cpp);
>> + u32 new_color;
>>
>> - pixel = *(u32 *)&buffer[src_offset];
>> + new_color = (src * 0xffff + dst * (0xffff - alpha));
>>
>> - return pixel;
>> + return DIV_ROUND_CLOSEST(new_color, 0xffff);
>> }
>>
>> /**
>> - * compute_crc - Compute CRC value on output frame
>> + * pre_mul_alpha_blend - alpha blending equation
>> + * @src_frame_info: source framebuffer's metadata
>> + * @stage_buffer: The line with the pixels from src_plane
>> + * @output_buffer: A line buffer that receives all the blends output
>> *
>> - * @vaddr: address to final framebuffer
>> - * @frame_info: framebuffer's metadata
>> + * Using the information from the `frame_info`, this blends only the
>> + * necessary pixels from the `stage_buffer` to the `output_buffer`
>> + * using premultiplied blend formula.
>> *
>> - * returns CRC value computed using crc32 on the visible portion of
>> - * the final framebuffer at vaddr_out
>> + * The current DRM assumption is that pixel color values have been already
>> + * pre-multiplied with the alpha channel values. See more
>> + * drm_plane_create_blend_mode_property(). Also, this formula assumes a
>> + * completely opaque background.
>> */
>> -static uint32_t compute_crc(const u8 *vaddr,
>> - const struct vkms_frame_info *frame_info)
>> +static void pre_mul_alpha_blend(struct vkms_frame_info *frame_info,
>> + struct line_buffer *stage_buffer,
>> + struct line_buffer *output_buffer)
>> {
>> - int x, y;
>> - u32 crc = 0, pixel = 0;
>> - int x_src = frame_info->src.x1 >> 16;
>> - int y_src = frame_info->src.y1 >> 16;
>> - int h_src = drm_rect_height(&frame_info->src) >> 16;
>> - int w_src = drm_rect_width(&frame_info->src) >> 16;
>> -
>> - for (y = y_src; y < y_src + h_src; ++y) {
>> - for (x = x_src; x < x_src + w_src; ++x) {
>> - pixel = get_pixel_from_buffer(x, y, vaddr, frame_info);
>> - crc = crc32_le(crc, (void *)&pixel, sizeof(u32));
>> - }
>> + int x_dst = frame_info->dst.x1;
>> + struct pixel_argb_u16 *out = output_buffer->pixels + x_dst;
>> + struct pixel_argb_u16 *in = stage_buffer->pixels;
>> + int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst),
>> + stage_buffer->n_pixels);
>> +
>> + for (int x = 0; x < x_limit; x++) {
>> + out[x].a = (u16)0xffff;
>> + out[x].r = pre_mul_blend_channel(in[x].r, out[x].r, in[x].a);
>> + out[x].g = pre_mul_blend_channel(in[x].g, out[x].g, in[x].a);
>> + out[x].b = pre_mul_blend_channel(in[x].b, out[x].b, in[x].a);
>> }
>> -
>> - return crc;
>> }
>>
>> -static u8 blend_channel(u8 src, u8 dst, u8 alpha)
>> +static bool check_y_limit(struct vkms_frame_info *frame_info, int y)
>> {
>> - u32 pre_blend;
>> - u8 new_color;
>> -
>> - pre_blend = (src * 255 + dst * (255 - alpha));
>> -
>> - /* Faster div by 255 */
>> - new_color = ((pre_blend + ((pre_blend + 257) >> 8)) >> 8);
>> + if (y >= frame_info->dst.y1 && y < frame_info->dst.y2)
>> + return true;
>>
>> - return new_color;
>> + return false;
>> }
>>
>> /**
>> - * alpha_blend - alpha blending equation
>> - * @argb_src: src pixel on premultiplied alpha mode
>> - * @argb_dst: dst pixel completely opaque
>> + * @wb_frame_info: The writeback frame buffer metadata
>> + * @crtc_state: The crtc state
>> + * @crc32: The crc output of the final frame
>> + * @output_buffer: A buffer of a row that will receive the result of the blend(s)
>> + * @stage_buffer: The line with the pixels from plane being blend to the output
>> *
>> - * blend pixels using premultiplied blend formula. The current DRM assumption
>> - * is that pixel color values have been already pre-multiplied with the alpha
>> - * channel values. See more drm_plane_create_blend_mode_property(). Also, this
>> - * formula assumes a completely opaque background.
>> + * This function blends the pixels (Using the `pre_mul_alpha_blend`)
>> + * from all planes, calculates the crc32 of the output from the former step,
>> + * and, if necessary, convert and store the output to the writeback buffer.
>> */
>> -static void alpha_blend(const u8 *argb_src, u8 *argb_dst)
>> +static void blend(struct vkms_writeback_job *wb,
>> + struct vkms_crtc_state *crtc_state,
>> + u32 *crc32, struct line_buffer *stage_buffer,
>> + struct line_buffer *output_buffer, size_t row_size)
>> {
>> - u8 alpha;
>> + struct vkms_plane_state **plane = crtc_state->active_planes;
>> + struct vkms_frame_info *primary_plane_info = plane[0]->frame_info;
>> + u32 n_active_planes = crtc_state->num_active_planes;
>> +
>> + int y_dst = primary_plane_info->dst.y1;
>> + int h_dst = drm_rect_height(&primary_plane_info->dst);
>> + int y_limit = y_dst + h_dst;
>> +
>> + for (size_t y = y_dst; y < y_limit; y++) {
>> + plane[0]->plane_read(output_buffer, primary_plane_info, y);
>> +
>> + /* If there are other planes besides primary, we consider the active
>> + * planes should be in z-order and compose them associatively:
>> + * ((primary <- overlay) <- cursor)
>> + */
>> + for (size_t i = 1; i < n_active_planes; i++) {
>> + if (!check_y_limit(plane[i]->frame_info, y))
>> + continue;
>> +
>> + plane[i]->plane_read(stage_buffer, plane[i]->frame_info, y);
>> + pre_mul_alpha_blend(plane[i]->frame_info, stage_buffer,
>> + output_buffer);
>> + }
>> +
>> + *crc32 = crc32_le(*crc32, (void *)output_buffer->pixels, row_size);
>>
>> - alpha = argb_src[3];
>> - argb_dst[0] = blend_channel(argb_src[0], argb_dst[0], alpha);
>> - argb_dst[1] = blend_channel(argb_src[1], argb_dst[1], alpha);
>> - argb_dst[2] = blend_channel(argb_src[2], argb_dst[2], alpha);
>> + if (wb)
>> + wb->wb_write(&wb->wb_frame_info, output_buffer, y);
>> + }
>> }
>>
>> -/**
>> - * x_blend - blending equation that ignores the pixel alpha
>> - *
>> - * overwrites RGB color value from src pixel to dst pixel.
>> - */
>> -static void x_blend(const u8 *xrgb_src, u8 *xrgb_dst)
>> +static int check_format_funcs(struct vkms_crtc_state *crtc_state,
>> + struct vkms_writeback_job *active_wb)
>> {
>> - memcpy(xrgb_dst, xrgb_src, sizeof(u8) * 3);
>> + struct vkms_plane_state **planes = crtc_state->active_planes;
>> + u32 n_active_planes = crtc_state->num_active_planes;
>> +
>> + for (size_t i = 0; i < n_active_planes; i++)
>> + if (!planes[i]->plane_read)
>> + return -1;
>> +
>> + if (active_wb && !active_wb->wb_write)
>> + return -1;
>> +
>> + return 0;
>> }
>>
>> -/**
>> - * blend - blend value at vaddr_src with value at vaddr_dst
>> - * @vaddr_dst: destination address
>> - * @vaddr_src: source address
>> - * @dst_frame_info: destination framebuffer's metadata
>> - * @src_frame_info: source framebuffer's metadata
>> - * @pixel_blend: blending equation based on plane format
>> - *
>> - * Blend the vaddr_src value with the vaddr_dst value using a pixel blend
>> - * equation according to the supported plane formats DRM_FORMAT_(A/XRGB8888)
>> - * and clearing alpha channel to an completely opaque background. This function
>> - * uses buffer's metadata to locate the new composite values at vaddr_dst.
>> - *
>> - * TODO: completely clear the primary plane (a = 0xff) before starting to blend
>> - * pixel color values
>> - */
>> -static void blend(void *vaddr_dst, void *vaddr_src,
>> - struct vkms_frame_info *dst_frame_info,
>> - struct vkms_frame_info *src_frame_info,
>> - void (*pixel_blend)(const u8 *, u8 *))
>> +static int compose_active_planes(struct vkms_writeback_job *active_wb,
>> + struct vkms_crtc_state *crtc_state,
>> + u32 *crc32)
>> {
>> - int i, j, j_dst, i_dst;
>> - int offset_src, offset_dst;
>> - u8 *pixel_dst, *pixel_src;
>> -
>> - int x_src = src_frame_info->src.x1 >> 16;
>> - int y_src = src_frame_info->src.y1 >> 16;
>> -
>> - int x_dst = src_frame_info->dst.x1;
>> - int y_dst = src_frame_info->dst.y1;
>> - int h_dst = drm_rect_height(&src_frame_info->dst);
>> - int w_dst = drm_rect_width(&src_frame_info->dst);
>> -
>> - int y_limit = y_src + h_dst;
>> - int x_limit = x_src + w_dst;
>> -
>> - for (i = y_src, i_dst = y_dst; i < y_limit; ++i) {
>> - for (j = x_src, j_dst = x_dst; j < x_limit; ++j) {
>> - offset_dst = dst_frame_info->offset
>> - + (i_dst * dst_frame_info->pitch)
>> - + (j_dst++ * dst_frame_info->cpp);
>> - offset_src = src_frame_info->offset
>> - + (i * src_frame_info->pitch)
>> - + (j * src_frame_info->cpp);
>> -
>> - pixel_src = (u8 *)(vaddr_src + offset_src);
>> - pixel_dst = (u8 *)(vaddr_dst + offset_dst);
>> - pixel_blend(pixel_src, pixel_dst);
>> - /* clearing alpha channel (0xff)*/
>> - pixel_dst[3] = 0xff;
>> - }
>> - i_dst++;
>> + size_t line_width, pixel_size = sizeof(struct pixel_argb_u16);
>> + struct vkms_frame_info *primary_plane_info = NULL;
>> + struct line_buffer output_buffer, stage_buffer;
>> + struct vkms_plane_state *act_plane = NULL;
>> + int ret = 0;
>> +
>> + /*
>> + * This check exists so we can call `crc32_le` for the entire line
>> + * instead doing it for each channel of each pixel in case
>> + * `struct `pixel_argb_u16` had any gap added by the compiler
>> + * between the struct fields.
>> + */
>> + static_assert(sizeof(struct pixel_argb_u16) == 8);
>> +
>> + if (crtc_state->num_active_planes >= 1) {
>> + act_plane = crtc_state->active_planes[0];
>> + if (act_plane->base.base.plane->type == DRM_PLANE_TYPE_PRIMARY)
>> + primary_plane_info = act_plane->frame_info;
>> }
>> -}
>>
>> -static void compose_plane(struct vkms_frame_info *primary_plane_info,
>> - struct vkms_frame_info *plane_frame_info,
>> - void *vaddr_out)
>> -{
>> - struct drm_framebuffer *fb = plane_frame_info->fb;
>> - void *vaddr;
>> - void (*pixel_blend)(const u8 *p_src, u8 *p_dst);
>> + if (!primary_plane_info)
>> + return -EINVAL;
>>
>> if (WARN_ON(iosys_map_is_null(&primary_plane_info->map[0])))
>> - return;
>> + return -EINVAL;
>>
>> - vaddr = plane_frame_info->map[0].vaddr;
>> + if (WARN_ON(check_format_funcs(crtc_state, active_wb)))
>> + return -EINVAL;
>>
>> - if (fb->format->format == DRM_FORMAT_ARGB8888)
>> - pixel_blend = &alpha_blend;
>> - else
>> - pixel_blend = &x_blend;
>> + line_width = drm_rect_width(&primary_plane_info->dst);
>> + stage_buffer.n_pixels = line_width;
>> + output_buffer.n_pixels = line_width;
>>
>> - blend(vaddr_out, vaddr, primary_plane_info,
>> - plane_frame_info, pixel_blend);
>> -}
>> + stage_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL);
>> + if (!stage_buffer.pixels) {
>> + DRM_ERROR("Cannot allocate memory for the output line buffer");
>> + return -ENOMEM;
>> + }
>>
>> -static int compose_active_planes(void **vaddr_out,
>> - struct vkms_frame_info *primary_plane_info,
>> - struct vkms_crtc_state *crtc_state)
>> -{
>> - struct drm_framebuffer *fb = primary_plane_info->fb;
>> - struct drm_gem_object *gem_obj = drm_gem_fb_get_obj(fb, 0);
>> - const void *vaddr;
>> - int i;
>> -
>> - if (!*vaddr_out) {
>> - *vaddr_out = kvzalloc(gem_obj->size, GFP_KERNEL);
>> - if (!*vaddr_out) {
>> - DRM_ERROR("Cannot allocate memory for output frame.");
>> - return -ENOMEM;
>> - }
>> + output_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL);
>> + if (!output_buffer.pixels) {
>> + DRM_ERROR("Cannot allocate memory for intermediate line buffer");
>> + ret = -ENOMEM;
>> + goto free_stage_buffer;
>> }
>>
>> - if (WARN_ON(iosys_map_is_null(&primary_plane_info->map[0])))
>> - return -EINVAL;
>> + if (active_wb) {
>> + struct vkms_frame_info *wb_frame_info = &active_wb->wb_frame_info;
>>
>> - vaddr = primary_plane_info->map[0].vaddr;
>> + wb_frame_info->src = primary_plane_info->src;
>> + wb_frame_info->dst = primary_plane_info->dst;
>> + }
>>
>> - memcpy(*vaddr_out, vaddr, gem_obj->size);
>> + blend(active_wb, crtc_state, crc32, &stage_buffer,
>> + &output_buffer, line_width * pixel_size);
>>
>> - /* If there are other planes besides primary, we consider the active
>> - * planes should be in z-order and compose them associatively:
>> - * ((primary <- overlay) <- cursor)
>> - */
>> - for (i = 1; i < crtc_state->num_active_planes; i++)
>> - compose_plane(primary_plane_info,
>> - crtc_state->active_planes[i]->frame_info,
>> - *vaddr_out);
>> + kvfree(output_buffer.pixels);
>> +free_stage_buffer:
>> + kvfree(stage_buffer.pixels);
>>
>> - return 0;
>> + return ret;
>> }
>>
>> /**
>> @@ -222,13 +206,11 @@ void vkms_composer_worker(struct work_struct *work)
>> struct vkms_crtc_state,
>> composer_work);
>> struct drm_crtc *crtc = crtc_state->base.crtc;
>> + struct vkms_writeback_job *active_wb = crtc_state->active_writeback;
>> struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
>> - struct vkms_frame_info *primary_plane_info = NULL;
>> - struct vkms_plane_state *act_plane = NULL;
>> bool crc_pending, wb_pending;
>> - void *vaddr_out = NULL;
>> - u32 crc32 = 0;
>> u64 frame_start, frame_end;
>> + u32 crc32 = 0;
>> int ret;
>>
>> spin_lock_irq(&out->composer_lock);
>> @@ -248,35 +230,19 @@ void vkms_composer_worker(struct work_struct *work)
>> if (!crc_pending)
>> return;
>>
>> - if (crtc_state->num_active_planes >= 1) {
>> - act_plane = crtc_state->active_planes[0];
>> - if (act_plane->base.base.plane->type == DRM_PLANE_TYPE_PRIMARY)
>> - primary_plane_info = act_plane->frame_info;
>> - }
>> -
>> - if (!primary_plane_info)
>> - return;
>> -
>> if (wb_pending)
>> - vaddr_out = crtc_state->active_writeback->data[0].vaddr;
>> + ret = compose_active_planes(active_wb, crtc_state, &crc32);
>> + else
>> + ret = compose_active_planes(NULL, crtc_state, &crc32);
>>
>> - ret = compose_active_planes(&vaddr_out, primary_plane_info,
>> - crtc_state);
>> - if (ret) {
>> - if (ret == -EINVAL && !wb_pending)
>> - kvfree(vaddr_out);
>> + if (ret)
>> return;
>> - }
>> -
>> - crc32 = compute_crc(vaddr_out, primary_plane_info);
>>
>> if (wb_pending) {
>> drm_writeback_signal_completion(&out->wb_connector, 0);
>> spin_lock_irq(&out->composer_lock);
>> crtc_state->wb_pending = false;
>> spin_unlock_irq(&out->composer_lock);
>> - } else {
>> - kvfree(vaddr_out);
>> }
>>
>> /*
>> diff --git a/drivers/gpu/drm/vkms/vkms_formats.c b/drivers/gpu/drm/vkms/vkms_formats.c
>> new file mode 100644
>> index 000000000000..ca4bfcac686b
>> --- /dev/null
>> +++ b/drivers/gpu/drm/vkms/vkms_formats.c
>> @@ -0,0 +1,155 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +
>> +#include <drm/drm_rect.h>
>> +#include <linux/minmax.h>
>> +
>> +#include "vkms_formats.h"
>> +
>> +static size_t pixel_offset(const struct vkms_frame_info *frame_info, int x, int y)
>> +{
>> + return frame_info->offset + (y * frame_info->pitch)
>> + + (x * frame_info->cpp);
>> +}
>> +
>> +/*
>> + * packed_pixels_addr - Get the pointer to pixel of a given pair of coordinates
>> + *
>> + * @frame_info: Buffer metadata
>> + * @x: The x(width) coordinate of the 2D buffer
>> + * @y: The y(Heigth) coordinate of the 2D buffer
>> + *
>> + * 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).
>> + */
>> +static void *packed_pixels_addr(const struct vkms_frame_info *frame_info,
>> + int x, int y)
>> +{
>> + size_t offset = pixel_offset(frame_info, x, y);
>> +
>> + return (u8 *)frame_info->map[0].vaddr + offset;
>> +}
>> +
>> +static void *get_packed_src_addr(const struct vkms_frame_info *frame_info, int y)
>> +{
>> + int x_src = frame_info->src.x1 >> 16;
>> + int y_src = y - frame_info->dst.y1 + (frame_info->src.y1 >> 16);
>> +
>> + return packed_pixels_addr(frame_info, x_src, y_src);
>> +}
>> +
>> +static void ARGB8888_to_argb_u16(struct line_buffer *stage_buffer,
>> + const struct vkms_frame_info *frame_info, int y)
>> +{
>> + struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
>> + u8 *src_pixels = get_packed_src_addr(frame_info, y);
>> + int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst),
>> + stage_buffer->n_pixels);
>> +
>> + for (size_t x = 0; x < x_limit; x++, src_pixels += 4) {
>> + /*
>> + * The 257 is the "conversion ratio". This number is obtained by the
>> + * (2^16 - 1) / (2^8 - 1) division. Which, in this case, tries to get
>> + * the best color value in a pixel format with more possibilities.
>> + * A similar idea applies to others RGB color conversions.
>> + */
>> + out_pixels[x].a = (u16)src_pixels[3] * 257;
>> + out_pixels[x].r = (u16)src_pixels[2] * 257;
>> + out_pixels[x].g = (u16)src_pixels[1] * 257;
>> + out_pixels[x].b = (u16)src_pixels[0] * 257;
>> + }
>> +}
>> +
>> +static void XRGB8888_to_argb_u16(struct line_buffer *stage_buffer,
>> + const struct vkms_frame_info *frame_info, int y)
>> +{
>> + struct pixel_argb_u16 *out_pixels = stage_buffer->pixels;
>> + u8 *src_pixels = get_packed_src_addr(frame_info, y);
>> + int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst),
>> + stage_buffer->n_pixels);
>> +
>> + for (size_t x = 0; x < x_limit; x++, src_pixels += 4) {
>> + out_pixels[x].a = (u16)0xffff;
>> + out_pixels[x].r = (u16)src_pixels[2] * 257;
>> + out_pixels[x].g = (u16)src_pixels[1] * 257;
>> + out_pixels[x].b = (u16)src_pixels[0] * 257;
>> + }
>> +}
>> +
>> +/*
>> + * 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.
>> + *
>> + * They are used in the `compose_active_planes` to convert and store a line
>> + * from the src_buffer to the writeback buffer.
>> + */
>> +static void argb_u16_to_ARGB8888(struct vkms_frame_info *frame_info,
>> + const struct line_buffer *src_buffer, int y)
>> +{
>> + int x_dst = frame_info->dst.x1;
>> + u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, 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);
>> +
>> + for (size_t x = 0; x < x_limit; x++, dst_pixels += 4) {
>> + /*
>> + * This sequence below is important because the format's byte order is
>> + * in little-endian. In the case of the ARGB8888 the memory is
>> + * organized this way:
>> + *
>> + * | Addr | = blue channel
>> + * | Addr + 1 | = green channel
>> + * | Addr + 2 | = Red channel
>> + * | Addr + 3 | = Alpha channel
>> + */
>> + dst_pixels[3] = DIV_ROUND_CLOSEST(in_pixels[x].a, 257);
>> + dst_pixels[2] = DIV_ROUND_CLOSEST(in_pixels[x].r, 257);
>> + dst_pixels[1] = DIV_ROUND_CLOSEST(in_pixels[x].g, 257);
>> + dst_pixels[0] = DIV_ROUND_CLOSEST(in_pixels[x].b, 257);
>> + }
>> +}
>> +
>> +static void argb_u16_to_XRGB8888(struct vkms_frame_info *frame_info,
>> + const struct line_buffer *src_buffer, int y)
>> +{
>> + int x_dst = frame_info->dst.x1;
>> + u8 *dst_pixels = packed_pixels_addr(frame_info, x_dst, 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);
>> +
>> + for (size_t x = 0; x < x_limit; x++, dst_pixels += 4) {
>> + dst_pixels[3] = 0xff;
>> + dst_pixels[2] = DIV_ROUND_CLOSEST(in_pixels[x].r, 257);
>> + dst_pixels[1] = DIV_ROUND_CLOSEST(in_pixels[x].g, 257);
>> + dst_pixels[0] = DIV_ROUND_CLOSEST(in_pixels[x].b, 257);
>> + }
>> +}
>> +
>> +frame_to_line_func get_frame_to_line_function(u32 format)
>> +{
>> + switch (format) {
>> + case DRM_FORMAT_ARGB8888:
>> + return &ARGB8888_to_argb_u16;
>> + case DRM_FORMAT_XRGB8888:
>> + return &XRGB8888_to_argb_u16;
>> + default:
>> + return NULL;
>> + }
>> +}
>> +
>> +line_to_frame_func get_line_to_frame_function(u32 format)
>> +{
>> + switch (format) {
>> + case DRM_FORMAT_ARGB8888:
>> + return &argb_u16_to_ARGB8888;
>> + case DRM_FORMAT_XRGB8888:
>> + return &argb_u16_to_XRGB8888;
>> + default:
>> + return NULL;
>> + }
>> +}
>> diff --git a/drivers/gpu/drm/vkms/vkms_formats.h b/drivers/gpu/drm/vkms/vkms_formats.h
>> new file mode 100644
>> index 000000000000..053ca42d5b31
>> --- /dev/null
>> +++ b/drivers/gpu/drm/vkms/vkms_formats.h
>> @@ -0,0 +1,12 @@
>> +// SPDX-License-Identifier: GPL-2.0+
>> +
>> +#ifndef _VKMS_FORMATS_H_
>> +#define _VKMS_FORMATS_H_
>> +
>> +#include "vkms_drv.h"
>> +
>> +frame_to_line_func get_frame_to_line_function(u32 format);
>> +
>> +line_to_frame_func get_line_to_frame_function(u32 format);
>> +
>> +#endif /* _VKMS_FORMATS_H_ */
>> diff --git a/drivers/gpu/drm/vkms/vkms_plane.c b/drivers/gpu/drm/vkms/vkms_plane.c
>> index 8adbfdc05e50..7a479a714565 100644
>> --- a/drivers/gpu/drm/vkms/vkms_plane.c
>> +++ b/drivers/gpu/drm/vkms/vkms_plane.c
>> @@ -10,6 +10,7 @@
>> #include <drm/drm_plane_helper.h>
>>
>> #include "vkms_drv.h"
>> +#include "vkms_formats.h"
> ^ this line no longer applies (needs to rebase), but I can manage it before apply to drm-misc-next
I did the rebase and I hadn't any issues.
I'm using `git://anongit.freedesktop.org/drm/drm-misc` remote. Should I
be using another git remote for vkms?
>>
>> static const u32 vkms_formats[] = {
>> DRM_FORMAT_XRGB8888,
>> @@ -100,6 +101,7 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
>> struct drm_shadow_plane_state *shadow_plane_state;
>> struct drm_framebuffer *fb = new_state->fb;
>> struct vkms_frame_info *frame_info;
>> + u32 fmt = fb->format->format;
>>
>> if (!new_state->crtc || !fb)
>> return;
>> @@ -116,6 +118,7 @@ static void vkms_plane_atomic_update(struct drm_plane *plane,
>> frame_info->offset = fb->offsets[0];
>> frame_info->pitch = fb->pitches[0];
>> frame_info->cpp = fb->format->cpp[0];
>> + vkms_plane_state->plane_read = get_frame_to_line_function(fmt);
>> }
>>
>> static int vkms_plane_atomic_check(struct drm_plane *plane,
>> diff --git a/drivers/gpu/drm/vkms/vkms_writeback.c b/drivers/gpu/drm/vkms/vkms_writeback.c
>> index c87f6c89e7b4..d2aabb52cb46 100644
>> --- a/drivers/gpu/drm/vkms/vkms_writeback.c
>> +++ b/drivers/gpu/drm/vkms/vkms_writeback.c
>> @@ -11,6 +11,7 @@
>> #include <drm/drm_gem_shmem_helper.h>
>>
>> #include "vkms_drv.h"
>> +#include "vkms_formats.h"
>>
>> static const u32 vkms_wb_formats[] = {
>> DRM_FORMAT_XRGB8888,
>> @@ -123,6 +124,7 @@ static void vkms_wb_atomic_commit(struct drm_connector *conn,
>> struct drm_framebuffer *fb = connector_state->writeback_job->fb;
>> struct vkms_writeback_job *active_wb;
>> struct vkms_frame_info *wb_frame_info;
>> + u32 wb_format = fb->format->format;
>>
>> if (!conn_state)
>> return;
>> @@ -140,6 +142,7 @@ 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->wb_write = get_line_to_frame_function(wb_format);
>> }
>>
>> static const struct drm_connector_helper_funcs vkms_wb_conn_helper_funcs = {
>> --
>> 2.30.2
>>
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