On Fri, Feb 4, 2022 at 10:53 AM Thomas Zimmermann <tzimmermann@xxxxxxx> wrote: > > Hi > > Am 04.02.22 um 14:43 schrieb Javier Martinez Canillas: > > Add support to convert XR24 and 8-bit grayscale to reversed monochrome for > > drivers that control monochromatic panels, that only have 1 bit per pixel. > > > > The drm_fb_gray8_to_mono_reversed() helper was based on the function that > > does the same in the drivers/gpu/drm/tiny/repaper.c driver. > > > > Signed-off-by: Javier Martinez Canillas <javierm@xxxxxxxxxx> > > --- > > > > (no changes since v1) > > > > drivers/gpu/drm/drm_format_helper.c | 80 +++++++++++++++++++++++++++++ > > include/drm/drm_format_helper.h | 7 +++ > > 2 files changed, 87 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_format_helper.c b/drivers/gpu/drm/drm_format_helper.c > > index 0f28dd2bdd72..cdce4b7c25d9 100644 > > --- a/drivers/gpu/drm/drm_format_helper.c > > +++ b/drivers/gpu/drm/drm_format_helper.c > > @@ -584,3 +584,83 @@ int drm_fb_blit_toio(void __iomem *dst, unsigned int dst_pitch, uint32_t dst_for > > return -EINVAL; > > } > > EXPORT_SYMBOL(drm_fb_blit_toio); > > + > > +static void drm_fb_gray8_to_mono_reversed_line(u8 *dst, const u8 *src, size_t pixels) > > +{ > > + unsigned int xb, i; > > + > > + for (xb = 0; xb < pixels / 8; xb++) { > > In practice, all mode widths are multiples of 8 because VGA mandated it. > So it's ok-ish to assume this here. You should probably at least print a > warning somewhere if (pixels % 8 != 0) Not sure if it's relevant, but 1366x768 was a fairly popular laptop resolution. There's even a dedicated drm_mode_fixup_1366x768 in drm_edid.c. (Would it have killed them to add 2 more horizontal pixels? Apparently.) Cheers, -ilia