| Message ID | 20220216072625.16947-1-schmitzmic@gmail.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | [v1] video/fbdev: Atari 2 bpp (STe) palette bugfix | expand |
On 2/16/22 08:26, Michael Schmitz wrote: > The code to set the shifter STe palette registers has a long > standing operator precedence bug, manifesting as colors set > on a 2 bits per pixel frame buffer coming up with a distinctive > blue tint. > > Add parentheses around the calculation of the per-color palette > data before shifting those into their respective bit field position. > > This bug goes back a long way (2.4 days at the very least) so there > won't be a Fixes: tag. > > Tested on ARAnyM as well on Falcon030 hardware. > > Cc: stable@vger.kernel.org > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Link: https://lore.kernel.org/all/CAMuHMdU3ievhXxKR_xi_v3aumnYW7UNUO6qMdhgfyWTyVSsCkQ@mail.gmail.com > Tested-by: Michael Schmitz <schmitzmic@gmail.com> > Signed-off-by: Michael Schmitz <schmitzmic@gmail.com> applied. Thanks! Helge > --- > drivers/video/fbdev/atafb.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/drivers/video/fbdev/atafb.c b/drivers/video/fbdev/atafb.c > index e3812a8ff55a..29e650ecfceb 100644 > --- a/drivers/video/fbdev/atafb.c > +++ b/drivers/video/fbdev/atafb.c > @@ -1683,9 +1683,9 @@ static int falcon_setcolreg(unsigned int regno, unsigned int red, > ((blue & 0xfc00) >> 8)); > if (regno < 16) { > shifter_tt.color_reg[regno] = > - (((red & 0xe000) >> 13) | ((red & 0x1000) >> 12) << 8) | > - (((green & 0xe000) >> 13) | ((green & 0x1000) >> 12) << 4) | > - ((blue & 0xe000) >> 13) | ((blue & 0x1000) >> 12); > + ((((red & 0xe000) >> 13) | ((red & 0x1000) >> 12)) << 8) | > + ((((green & 0xe000) >> 13) | ((green & 0x1000) >> 12)) << 4) | > + ((blue & 0xe000) >> 13) | ((blue & 0x1000) >> 12); > ((u32 *)info->pseudo_palette)[regno] = ((red & 0xf800) | > ((green & 0xfc00) >> 5) | > ((blue & 0xf800) >> 11)); > @@ -1971,9 +1971,9 @@ static int stste_setcolreg(unsigned int regno, unsigned int red, > green >>= 12; > if (ATARIHW_PRESENT(EXTD_SHIFTER)) > shifter_tt.color_reg[regno] = > - (((red & 0xe) >> 1) | ((red & 1) << 3) << 8) | > - (((green & 0xe) >> 1) | ((green & 1) << 3) << 4) | > - ((blue & 0xe) >> 1) | ((blue & 1) << 3); > + ((((red & 0xe) >> 1) | ((red & 1) << 3)) << 8) | > + ((((green & 0xe) >> 1) | ((green & 1) << 3)) << 4) | > + ((blue & 0xe) >> 1) | ((blue & 1) << 3); > else > shifter_tt.color_reg[regno] = > ((red & 0xe) << 7) | >
On Wed, Feb 16, 2022 at 8:26 AM Michael Schmitz <schmitzmic@gmail.com> wrote: > The code to set the shifter STe palette registers has a long > standing operator precedence bug, manifesting as colors set > on a 2 bits per pixel frame buffer coming up with a distinctive > blue tint. > > Add parentheses around the calculation of the per-color palette > data before shifting those into their respective bit field position. > > This bug goes back a long way (2.4 days at the very least) so there > won't be a Fixes: tag. > > Tested on ARAnyM as well on Falcon030 hardware. > > Cc: stable@vger.kernel.org > Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> > Link: https://lore.kernel.org/all/CAMuHMdU3ievhXxKR_xi_v3aumnYW7UNUO6qMdhgfyWTyVSsCkQ@mail.gmail.com > Tested-by: Michael Schmitz <schmitzmic@gmail.com> > Signed-off-by: Michael Schmitz <schmitzmic@gmail.com> Thanks, fixes the issue for me. Tested-by: Geert Uytterhoeven <geert@linux-m68k.org> Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
diff --git a/drivers/video/fbdev/atafb.c b/drivers/video/fbdev/atafb.c index e3812a8ff55a..29e650ecfceb 100644 --- a/drivers/video/fbdev/atafb.c +++ b/drivers/video/fbdev/atafb.c @@ -1683,9 +1683,9 @@ static int falcon_setcolreg(unsigned int regno, unsigned int red, ((blue & 0xfc00) >> 8)); if (regno < 16) { shifter_tt.color_reg[regno] = - (((red & 0xe000) >> 13) | ((red & 0x1000) >> 12) << 8) | - (((green & 0xe000) >> 13) | ((green & 0x1000) >> 12) << 4) | - ((blue & 0xe000) >> 13) | ((blue & 0x1000) >> 12); + ((((red & 0xe000) >> 13) | ((red & 0x1000) >> 12)) << 8) | + ((((green & 0xe000) >> 13) | ((green & 0x1000) >> 12)) << 4) | + ((blue & 0xe000) >> 13) | ((blue & 0x1000) >> 12); ((u32 *)info->pseudo_palette)[regno] = ((red & 0xf800) | ((green & 0xfc00) >> 5) | ((blue & 0xf800) >> 11)); @@ -1971,9 +1971,9 @@ static int stste_setcolreg(unsigned int regno, unsigned int red, green >>= 12; if (ATARIHW_PRESENT(EXTD_SHIFTER)) shifter_tt.color_reg[regno] = - (((red & 0xe) >> 1) | ((red & 1) << 3) << 8) | - (((green & 0xe) >> 1) | ((green & 1) << 3) << 4) | - ((blue & 0xe) >> 1) | ((blue & 1) << 3); + ((((red & 0xe) >> 1) | ((red & 1) << 3)) << 8) | + ((((green & 0xe) >> 1) | ((green & 1) << 3)) << 4) | + ((blue & 0xe) >> 1) | ((blue & 1) << 3); else shifter_tt.color_reg[regno] = ((red & 0xe) << 7) |