The previous memset operation was not correctly setting zero on the alpha channel to compute the crc, and as a result, the pipe-A-cursor-alpha-transparent subtest of the IGT test kms_cursor_crc was crashing. To avoid errors of misinterpretation related to endianness, this solution uses a bitfield operation to extract the RGB values from each pixel and ignores the alpha channel as expected.
Signed-off-by: Melissa Wen melissa.srw@gmail.com --- drivers/gpu/drm/vkms/vkms_composer.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/vkms/vkms_composer.c b/drivers/gpu/drm/vkms/vkms_composer.c index 4af2f19480f4..8c1c005bb717 100644 --- a/drivers/gpu/drm/vkms/vkms_composer.c +++ b/drivers/gpu/drm/vkms/vkms_composer.c @@ -1,6 +1,7 @@ // SPDX-License-Identifier: GPL-2.0+
#include <linux/crc32.h> +#include <linux/bitfield.h>
#include <drm/drm_atomic.h> #include <drm/drm_atomic_helper.h> @@ -9,6 +10,8 @@
#include "vkms_drv.h"
+#define XRGB_MSK GENMASK(23, 0) + /** * compute_crc - Compute CRC value on output frame * @@ -26,6 +29,7 @@ static uint32_t compute_crc(void *vaddr_out, struct vkms_composer *composer) int h_src = drm_rect_height(&composer->src) >> 16; int w_src = drm_rect_width(&composer->src) >> 16; u32 crc = 0; + u32 *pixel;
for (i = y_src; i < y_src + h_src; ++i) { for (j = x_src; j < x_src + w_src; ++j) { @@ -33,7 +37,8 @@ static uint32_t compute_crc(void *vaddr_out, struct vkms_composer *composer) + (i * composer->pitch) + (j * composer->cpp); /* XRGB format ignores Alpha channel */ - memset(vaddr_out + src_offset + 24, 0, 8); + pixel = vaddr_out + src_offset; + *pixel = FIELD_GET(XRGB_MSK, *(u32 *)pixel); crc = crc32_le(crc, vaddr_out + src_offset, sizeof(u32)); }