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![Igor Torrente](/assets/img/avatar_default.png)
We will remove the current assumption that the primary plane has the same size and position as CRTC and that the primary plane is the bottom-most in zpos order, or is even enabled. At least as far as the blending machinery is concerned. For that we will add CRTC dimension information to `vkms_crtc_state` and add a opaque black backgound color. Because now we need to fill the background, we had a loss in performance with this change. Results running the IGT[1] test `igt@kms_cursor_crc@pipe-a-cursor-512x512-onscreen` ten times: | Frametime | |:--------------------------------------------:| | Implementation | Previous | This commit | |:---------------:|:---------:|:--------------:| | frametime range | 5~18 ms | 10~22 ms | | Average | 8.47 ms | 12.32 ms | [1] IGT commit id: bc3f6833a12221a46659535dac06ebb312490eb4 V6: Improve the commit description (Pekka Paalanen). Update some comments (Pekka Paalanen). Remove some fields from `vkms_crtc_state` and move where some variables are set (Pekka Paalanen). Reviewed-by: Melissa Wen <mwen@igalia.com> Signed-off-by: Igor Torrente <igormtorrente@gmail.com> Signed-off-by: Melissa Wen <melissa.srw@gmail.com> Link: https://patchwork.freedesktop.org/patch/msgid/20220905190811.25024-8-igormtorrente@gmail.com
319 lines
8.7 KiB
C
319 lines
8.7 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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#include <linux/crc32.h>
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#include <drm/drm_atomic.h>
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#include <drm/drm_atomic_helper.h>
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#include <drm/drm_fourcc.h>
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#include <drm/drm_gem_framebuffer_helper.h>
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#include <drm/drm_vblank.h>
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#include <linux/minmax.h>
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#include "vkms_drv.h"
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static u16 pre_mul_blend_channel(u16 src, u16 dst, u16 alpha)
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{
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u32 new_color;
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new_color = (src * 0xffff + dst * (0xffff - alpha));
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return DIV_ROUND_CLOSEST(new_color, 0xffff);
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}
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/**
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* pre_mul_alpha_blend - alpha blending equation
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* @src_frame_info: source framebuffer's metadata
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* @stage_buffer: The line with the pixels from src_plane
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* @output_buffer: A line buffer that receives all the blends output
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*
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* Using the information from the `frame_info`, this blends only the
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* necessary pixels from the `stage_buffer` to the `output_buffer`
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* using premultiplied blend formula.
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*
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* The current DRM assumption is that pixel color values have been already
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* pre-multiplied with the alpha channel values. See more
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* drm_plane_create_blend_mode_property(). Also, this formula assumes a
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* completely opaque background.
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*/
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static void pre_mul_alpha_blend(struct vkms_frame_info *frame_info,
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struct line_buffer *stage_buffer,
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struct line_buffer *output_buffer)
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{
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int x_dst = frame_info->dst.x1;
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struct pixel_argb_u16 *out = output_buffer->pixels + x_dst;
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struct pixel_argb_u16 *in = stage_buffer->pixels;
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int x_limit = min_t(size_t, drm_rect_width(&frame_info->dst),
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stage_buffer->n_pixels);
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for (int x = 0; x < x_limit; x++) {
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out[x].a = (u16)0xffff;
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out[x].r = pre_mul_blend_channel(in[x].r, out[x].r, in[x].a);
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out[x].g = pre_mul_blend_channel(in[x].g, out[x].g, in[x].a);
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out[x].b = pre_mul_blend_channel(in[x].b, out[x].b, in[x].a);
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}
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}
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static bool check_y_limit(struct vkms_frame_info *frame_info, int y)
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{
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if (y >= frame_info->dst.y1 && y < frame_info->dst.y2)
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return true;
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return false;
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}
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static void fill_background(const struct pixel_argb_u16 *background_color,
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struct line_buffer *output_buffer)
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{
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for (size_t i = 0; i < output_buffer->n_pixels; i++)
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output_buffer->pixels[i] = *background_color;
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}
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/**
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* @wb_frame_info: The writeback frame buffer metadata
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* @crtc_state: The crtc state
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* @crc32: The crc output of the final frame
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* @output_buffer: A buffer of a row that will receive the result of the blend(s)
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* @stage_buffer: The line with the pixels from plane being blend to the output
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*
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* This function blends the pixels (Using the `pre_mul_alpha_blend`)
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* from all planes, calculates the crc32 of the output from the former step,
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* and, if necessary, convert and store the output to the writeback buffer.
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*/
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static void blend(struct vkms_writeback_job *wb,
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struct vkms_crtc_state *crtc_state,
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u32 *crc32, struct line_buffer *stage_buffer,
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struct line_buffer *output_buffer, size_t row_size)
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{
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struct vkms_plane_state **plane = crtc_state->active_planes;
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u32 n_active_planes = crtc_state->num_active_planes;
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const struct pixel_argb_u16 background_color = { .a = 0xffff };
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size_t crtc_y_limit = crtc_state->base.crtc->mode.vdisplay;
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for (size_t y = 0; y < crtc_y_limit; y++) {
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fill_background(&background_color, output_buffer);
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/* The active planes are composed associatively in z-order. */
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for (size_t i = 0; i < n_active_planes; i++) {
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if (!check_y_limit(plane[i]->frame_info, y))
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continue;
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plane[i]->plane_read(stage_buffer, plane[i]->frame_info, y);
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pre_mul_alpha_blend(plane[i]->frame_info, stage_buffer,
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output_buffer);
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}
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*crc32 = crc32_le(*crc32, (void *)output_buffer->pixels, row_size);
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if (wb)
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wb->wb_write(&wb->wb_frame_info, output_buffer, y);
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}
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}
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static int check_format_funcs(struct vkms_crtc_state *crtc_state,
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struct vkms_writeback_job *active_wb)
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{
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struct vkms_plane_state **planes = crtc_state->active_planes;
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u32 n_active_planes = crtc_state->num_active_planes;
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for (size_t i = 0; i < n_active_planes; i++)
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if (!planes[i]->plane_read)
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return -1;
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if (active_wb && !active_wb->wb_write)
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return -1;
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return 0;
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}
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static int check_iosys_map(struct vkms_crtc_state *crtc_state)
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{
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struct vkms_plane_state **plane_state = crtc_state->active_planes;
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u32 n_active_planes = crtc_state->num_active_planes;
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for (size_t i = 0; i < n_active_planes; i++)
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if (iosys_map_is_null(&plane_state[i]->frame_info->map[0]))
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return -1;
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return 0;
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}
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static int compose_active_planes(struct vkms_writeback_job *active_wb,
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struct vkms_crtc_state *crtc_state,
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u32 *crc32)
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{
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size_t line_width, pixel_size = sizeof(struct pixel_argb_u16);
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struct line_buffer output_buffer, stage_buffer;
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int ret = 0;
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/*
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* This check exists so we can call `crc32_le` for the entire line
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* instead doing it for each channel of each pixel in case
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* `struct `pixel_argb_u16` had any gap added by the compiler
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* between the struct fields.
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*/
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static_assert(sizeof(struct pixel_argb_u16) == 8);
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if (WARN_ON(check_iosys_map(crtc_state)))
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return -EINVAL;
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if (WARN_ON(check_format_funcs(crtc_state, active_wb)))
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return -EINVAL;
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line_width = crtc_state->base.crtc->mode.hdisplay;
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stage_buffer.n_pixels = line_width;
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output_buffer.n_pixels = line_width;
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stage_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL);
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if (!stage_buffer.pixels) {
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DRM_ERROR("Cannot allocate memory for the output line buffer");
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return -ENOMEM;
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}
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output_buffer.pixels = kvmalloc(line_width * pixel_size, GFP_KERNEL);
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if (!output_buffer.pixels) {
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DRM_ERROR("Cannot allocate memory for intermediate line buffer");
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ret = -ENOMEM;
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goto free_stage_buffer;
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}
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blend(active_wb, crtc_state, crc32, &stage_buffer,
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&output_buffer, line_width * pixel_size);
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kvfree(output_buffer.pixels);
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free_stage_buffer:
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kvfree(stage_buffer.pixels);
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return ret;
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}
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/**
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* vkms_composer_worker - ordered work_struct to compute CRC
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*
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* @work: work_struct
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*
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* Work handler for composing and computing CRCs. work_struct scheduled in
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* an ordered workqueue that's periodically scheduled to run by
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* vkms_vblank_simulate() and flushed at vkms_atomic_commit_tail().
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*/
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void vkms_composer_worker(struct work_struct *work)
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{
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struct vkms_crtc_state *crtc_state = container_of(work,
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struct vkms_crtc_state,
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composer_work);
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struct drm_crtc *crtc = crtc_state->base.crtc;
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struct vkms_writeback_job *active_wb = crtc_state->active_writeback;
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struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
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bool crc_pending, wb_pending;
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u64 frame_start, frame_end;
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u32 crc32 = 0;
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int ret;
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spin_lock_irq(&out->composer_lock);
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frame_start = crtc_state->frame_start;
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frame_end = crtc_state->frame_end;
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crc_pending = crtc_state->crc_pending;
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wb_pending = crtc_state->wb_pending;
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crtc_state->frame_start = 0;
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crtc_state->frame_end = 0;
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crtc_state->crc_pending = false;
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spin_unlock_irq(&out->composer_lock);
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/*
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* We raced with the vblank hrtimer and previous work already computed
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* the crc, nothing to do.
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*/
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if (!crc_pending)
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return;
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if (wb_pending)
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ret = compose_active_planes(active_wb, crtc_state, &crc32);
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else
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ret = compose_active_planes(NULL, crtc_state, &crc32);
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if (ret)
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return;
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if (wb_pending) {
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drm_writeback_signal_completion(&out->wb_connector, 0);
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spin_lock_irq(&out->composer_lock);
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crtc_state->wb_pending = false;
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spin_unlock_irq(&out->composer_lock);
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}
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/*
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* The worker can fall behind the vblank hrtimer, make sure we catch up.
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*/
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while (frame_start <= frame_end)
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drm_crtc_add_crc_entry(crtc, true, frame_start++, &crc32);
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}
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static const char * const pipe_crc_sources[] = {"auto"};
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const char *const *vkms_get_crc_sources(struct drm_crtc *crtc,
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size_t *count)
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{
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*count = ARRAY_SIZE(pipe_crc_sources);
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return pipe_crc_sources;
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}
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static int vkms_crc_parse_source(const char *src_name, bool *enabled)
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{
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int ret = 0;
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if (!src_name) {
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*enabled = false;
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} else if (strcmp(src_name, "auto") == 0) {
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*enabled = true;
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} else {
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*enabled = false;
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ret = -EINVAL;
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}
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return ret;
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}
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int vkms_verify_crc_source(struct drm_crtc *crtc, const char *src_name,
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size_t *values_cnt)
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{
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bool enabled;
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if (vkms_crc_parse_source(src_name, &enabled) < 0) {
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DRM_DEBUG_DRIVER("unknown source %s\n", src_name);
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return -EINVAL;
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}
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*values_cnt = 1;
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return 0;
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}
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void vkms_set_composer(struct vkms_output *out, bool enabled)
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{
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bool old_enabled;
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if (enabled)
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drm_crtc_vblank_get(&out->crtc);
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spin_lock_irq(&out->lock);
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old_enabled = out->composer_enabled;
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out->composer_enabled = enabled;
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spin_unlock_irq(&out->lock);
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if (old_enabled)
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drm_crtc_vblank_put(&out->crtc);
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}
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int vkms_set_crc_source(struct drm_crtc *crtc, const char *src_name)
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{
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struct vkms_output *out = drm_crtc_to_vkms_output(crtc);
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bool enabled = false;
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int ret = 0;
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ret = vkms_crc_parse_source(src_name, &enabled);
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vkms_set_composer(out, enabled);
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return ret;
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}
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