| Message ID | b47589ed5d8ca44e0956684412e3f16f3227f887.1657300532.git.geert@linux-m68k.org |
|---|---|
| State | New |
| Headers | show |
| Series | drm: Endianness fixes | expand |
Den 08.07.2022 20.21, skrev Geert Uytterhoeven: > DRM formats are defined to be little-endian, unless the > DRM_FORMAT_BIG_ENDIAN flag is set. Hence when converting from one > format to another, multi-byte pixel values loaded from memory must be > converted from little-endian to host-endian. Conversely, multi-byte > pixel values written to memory must be converted from host-endian to > little-endian. Currently only drm_fb_xrgb8888_to_rgb332_line() includes > endianness handling. > > Fix gud_xrgb8888_to_color() on big-endian platforms by adding the > missing endianness handling. > > Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> > --- > Compile-tested only. > > Interestingly, drm_fb_xrgb8888_to_rgb332() was introduced for GUD, > and always had correct endiannes handling... RGB332 support was added later and by that time I had understood that the framebuffer was little endian and not host endian as I first assumed (there's a fixme comment in gud_pipe.c that BE is probably broken but I haven't got any hw to test on so I haven't tried to fix it). Thanks for fixing this, pathces 2 and 3 tested on drm/gud and applied to drm-misc-next. Noralf. > --- > drivers/gpu/drm/gud/gud_pipe.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c > index 4873f9799f412e04..d42592f6daab8b2a 100644 > --- a/drivers/gpu/drm/gud/gud_pipe.c > +++ b/drivers/gpu/drm/gud/gud_pipe.c > @@ -105,7 +105,8 @@ static size_t gud_xrgb8888_to_color(u8 *dst, const struct drm_format_info *forma > unsigned int bits_per_pixel = 8 / block_width; > u8 r, g, b, pix, *block = dst; /* Assign to silence compiler warning */ > unsigned int x, y, width; > - u32 *pix32; > + __le32 *sbuf32; > + u32 pix32; > size_t len; > > /* Start on a byte boundary */ > @@ -114,8 +115,8 @@ static size_t gud_xrgb8888_to_color(u8 *dst, const struct drm_format_info *forma > len = drm_format_info_min_pitch(format, 0, width) * drm_rect_height(rect); > > for (y = rect->y1; y < rect->y2; y++) { > - pix32 = src + (y * fb->pitches[0]); > - pix32 += rect->x1; > + sbuf32 = src + (y * fb->pitches[0]); > + sbuf32 += rect->x1; > > for (x = 0; x < width; x++) { > unsigned int pixpos = x % block_width; /* within byte from the left */ > @@ -126,9 +127,10 @@ static size_t gud_xrgb8888_to_color(u8 *dst, const struct drm_format_info *forma > *block = 0; > } > > - r = *pix32 >> 16; > - g = *pix32 >> 8; > - b = *pix32++; > + pix32 = le32_to_cpu(*sbuf32++); > + r = pix32 >> 16; > + g = pix32 >> 8; > + b = pix32; > > switch (format->format) { > case GUD_DRM_FORMAT_XRGB1111:
diff --git a/drivers/gpu/drm/gud/gud_pipe.c b/drivers/gpu/drm/gud/gud_pipe.c index 4873f9799f412e04..d42592f6daab8b2a 100644 --- a/drivers/gpu/drm/gud/gud_pipe.c +++ b/drivers/gpu/drm/gud/gud_pipe.c @@ -105,7 +105,8 @@ static size_t gud_xrgb8888_to_color(u8 *dst, const struct drm_format_info *forma unsigned int bits_per_pixel = 8 / block_width; u8 r, g, b, pix, *block = dst; /* Assign to silence compiler warning */ unsigned int x, y, width; - u32 *pix32; + __le32 *sbuf32; + u32 pix32; size_t len; /* Start on a byte boundary */ @@ -114,8 +115,8 @@ static size_t gud_xrgb8888_to_color(u8 *dst, const struct drm_format_info *forma len = drm_format_info_min_pitch(format, 0, width) * drm_rect_height(rect); for (y = rect->y1; y < rect->y2; y++) { - pix32 = src + (y * fb->pitches[0]); - pix32 += rect->x1; + sbuf32 = src + (y * fb->pitches[0]); + sbuf32 += rect->x1; for (x = 0; x < width; x++) { unsigned int pixpos = x % block_width; /* within byte from the left */ @@ -126,9 +127,10 @@ static size_t gud_xrgb8888_to_color(u8 *dst, const struct drm_format_info *forma *block = 0; } - r = *pix32 >> 16; - g = *pix32 >> 8; - b = *pix32++; + pix32 = le32_to_cpu(*sbuf32++); + r = pix32 >> 16; + g = pix32 >> 8; + b = pix32; switch (format->format) { case GUD_DRM_FORMAT_XRGB1111:
DRM formats are defined to be little-endian, unless the DRM_FORMAT_BIG_ENDIAN flag is set. Hence when converting from one format to another, multi-byte pixel values loaded from memory must be converted from little-endian to host-endian. Conversely, multi-byte pixel values written to memory must be converted from host-endian to little-endian. Currently only drm_fb_xrgb8888_to_rgb332_line() includes endianness handling. Fix gud_xrgb8888_to_color() on big-endian platforms by adding the missing endianness handling. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> --- Compile-tested only. Interestingly, drm_fb_xrgb8888_to_rgb332() was introduced for GUD, and always had correct endiannes handling... --- drivers/gpu/drm/gud/gud_pipe.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-)