Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 51186190 authored by Michael Schmitz's avatar Michael Schmitz Committed by Greg Kroah-Hartman
Browse files

video: fbdev: atari: Atari 2 bpp (STe) palette bugfix 



commit c8be5edbd36ceed2ff3d6b8f8e40643c3f396ea3 upstream.

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: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Link: https://lore.kernel.org/all/CAMuHMdU3ievhXxKR_xi_v3aumnYW7UNUO6qMdhgfyWTyVSsCkQ@mail.gmail.com


Tested-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Tested-by: default avatarGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: default avatarMichael Schmitz <schmitzmic@gmail.com>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 478154be

drivers/video/fbdev/atafb.c

+6 −6
Original line number Diff line number Diff line
@@ -1692,8 +1692,8 @@ 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) |

			((((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) |
@@ -1980,8 +1980,8 @@ 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) |

			((((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] =