Hi Am 28.09.22 um 13:12 schrieb Michal Suchánek:
Hello, On Wed, Sep 28, 2022 at 12:50:10PM +0200, Thomas Zimmermann wrote:All DRM formats assume little-endian byte order. On big-endian systems, it is likely that the scanout buffer is in big endian as well. Update the format accordingly and add endianess conversion to the format-helper library. Also opt-in to allocated buffers in host format by default.This sounds backwards to me.
In which way?
Skimming through the code it sounds like the buffer is in fact in the same format all the time but when the CPU is switched to BE it sees the data loaded from it differently. Or am I missing something?
Which buffer do you mean? The scanout buffer coming from the firmware, or the GEM BOs that are allocated by renderers?
The scanout buffer is either in BE or LE format. According to the code in offb, it's signaled by a node in the device tree. I took that code into ofdrm and set the scanout format accordingly.
The GEM BO can be in any format. If necessary, ofdrm converts internally while copying it to the scanout buffer. The quirk we opt in, makes DRM prefer whatever default byteorder the host prefers (BE or LE). According to the docs, it's the right thing to do. But that only affects the GEM code, not the scanout buffer.
Best regards Thomas
Thanks MichalSuggested-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx> --- drivers/gpu/drm/drm_format_helper.c | 10 ++++++ drivers/gpu/drm/tiny/ofdrm.c | 55 +++++++++++++++++++++++++++-- 2 files changed, 63 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c index 4afc4ac27342..fca7936db083 100644 --- a/drivers/gpu/drm/drm_format_helper.c +++ b/drivers/gpu/drm/drm_format_helper.c @@ -659,6 +659,11 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d drm_fb_xrgb8888_to_rgb565(dst, dst_pitch, src, fb, clip, false); return 0; } + } else if (dst_format == (DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN)) { + if (fb_format == DRM_FORMAT_RGB565) { + drm_fb_swab(dst, dst_pitch, src, fb, clip, false); + return 0; + } } else if (dst_format == DRM_FORMAT_RGB888) { if (fb_format == DRM_FORMAT_XRGB8888) { drm_fb_xrgb8888_to_rgb888(dst, dst_pitch, src, fb, clip); @@ -677,6 +682,11 @@ int drm_fb_blit(struct iosys_map *dst, const unsigned int *dst_pitch, uint32_t d drm_fb_xrgb8888_to_xrgb2101010(dst, dst_pitch, src, fb, clip); return 0; } + } else if (dst_format == DRM_FORMAT_BGRX8888) { + if (fb_format == DRM_FORMAT_XRGB8888) { + drm_fb_swab(dst, dst_pitch, src, fb, clip, false); + return 0; + } }drm_warn_once(fb->dev, "No conversion helper from %p4cc to %p4cc found.\n",diff --git a/drivers/gpu/drm/tiny/ofdrm.c b/drivers/gpu/drm/tiny/ofdrm.c index 0bf5eebf6678..6e100a7f5db7 100644 --- a/drivers/gpu/drm/tiny/ofdrm.c +++ b/drivers/gpu/drm/tiny/ofdrm.c @@ -94,7 +94,7 @@ static int display_get_validated_int0(struct drm_device *dev, const char *name, }static const struct drm_format_info *display_get_validated_format(struct drm_device *dev,- u32 depth) + u32 depth, bool big_endian) { const struct drm_format_info *info; u32 format; @@ -115,6 +115,29 @@ static const struct drm_format_info *display_get_validated_format(struct drm_dev return ERR_PTR(-EINVAL); }+ /*+ * DRM formats assume little-endian byte order. Update the format + * if the scanout buffer uses big-endian ordering. + */ + if (big_endian) { + switch (format) { + case DRM_FORMAT_XRGB8888: + format = DRM_FORMAT_BGRX8888; + break; + case DRM_FORMAT_ARGB8888: + format = DRM_FORMAT_BGRA8888; + break; + case DRM_FORMAT_RGB565: + format = DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN; + break; + case DRM_FORMAT_XRGB1555: + format = DRM_FORMAT_XRGB1555 | DRM_FORMAT_BIG_ENDIAN; + break; + default: + break; + } + } + info = drm_format_info(format); if (!info) { drm_err(dev, "cannot find framebuffer format for depth %u\n", depth); @@ -134,6 +157,23 @@ static int display_read_u32_of(struct drm_device *dev, struct device_node *of_no return ret; }+static bool display_get_big_endian_of(struct drm_device *dev, struct device_node *of_node)+{ + bool big_endian; + +#ifdef __BIG_ENDIAN + big_endian = true; + if (of_get_property(of_node, "little-endian", NULL)) + big_endian = false; +#else + big_endian = false; + if (of_get_property(of_node, "big-endian", NULL)) + big_endian = true; +#endif + + return big_endian; +} + static int display_get_width_of(struct drm_device *dev, struct device_node *of_node) { u32 width; @@ -613,6 +653,7 @@ static void ofdrm_device_set_gamma_linear(struct ofdrm_device *odev,switch (format->format) {case DRM_FORMAT_RGB565: + case DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN: /* Use better interpolation, to take 32 values from 0 to 255 */ for (i = 0; i < OFDRM_GAMMA_LUT_SIZE / 8; i++) { unsigned char r = i * 8 + i / 4; @@ -631,6 +672,7 @@ static void ofdrm_device_set_gamma_linear(struct ofdrm_device *odev, } break; case DRM_FORMAT_XRGB8888: + case DRM_FORMAT_BGRX8888: for (i = 0; i < OFDRM_GAMMA_LUT_SIZE; i++) odev->funcs->cmap_write(odev, i, i, i, i); break; @@ -650,6 +692,7 @@ static void ofdrm_device_set_gamma(struct ofdrm_device *odev,switch (format->format) {case DRM_FORMAT_RGB565: + case DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN: /* Use better interpolation, to take 32 values from lut[0] to lut[255] */ for (i = 0; i < OFDRM_GAMMA_LUT_SIZE / 8; i++) { unsigned char r = lut[i * 8 + i / 4].red >> 8; @@ -668,6 +711,7 @@ static void ofdrm_device_set_gamma(struct ofdrm_device *odev, } break; case DRM_FORMAT_XRGB8888: + case DRM_FORMAT_BGRX8888: for (i = 0; i < OFDRM_GAMMA_LUT_SIZE; i++) { unsigned char r = lut[i].red >> 8; unsigned char g = lut[i].green >> 8; @@ -718,6 +762,9 @@ static const uint32_t ofdrm_primary_plane_formats[] = { DRM_FORMAT_RGB565, //DRM_FORMAT_XRGB1555, //DRM_FORMAT_C8, + /* Big-endian formats below */ + DRM_FORMAT_BGRX8888, + DRM_FORMAT_RGB565 | DRM_FORMAT_BIG_ENDIAN, };static const uint64_t ofdrm_primary_plane_format_modifiers[] = {@@ -1048,6 +1095,7 @@ static struct ofdrm_device *ofdrm_device_create(struct drm_driver *drv, struct ofdrm_device *odev; struct drm_device *dev; enum ofdrm_model model; + bool big_endian; int width, height, depth, linebytes; const struct drm_format_info *format; u64 address; @@ -1109,6 +1157,8 @@ static struct ofdrm_device *ofdrm_device_create(struct drm_driver *drv, break; }+ big_endian = display_get_big_endian_of(dev, of_node);+ width = display_get_width_of(dev, of_node); if (width < 0) return ERR_PTR(width); @@ -1122,7 +1172,7 @@ static struct ofdrm_device *ofdrm_device_create(struct drm_driver *drv, if (linebytes < 0) return ERR_PTR(linebytes);- format = display_get_validated_format(dev, depth);+ format = display_get_validated_format(dev, depth, big_endian); if (IS_ERR(format)) return ERR_CAST(format); if (!linebytes) { @@ -1234,6 +1284,7 @@ static struct ofdrm_device *ofdrm_device_create(struct drm_driver *drv, dev->mode_config.preferred_depth = depth; break; } + dev->mode_config.quirk_addfb_prefer_host_byte_order = true;/* Primary plane */ --2.37.3
-- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 Nürnberg, Germany (HRB 36809, AG Nürnberg) Geschäftsführer: Ivo Totev
Attachment:
OpenPGP_signature
Description: OpenPGP digital signature
