"Pierre Asselin" <pa@xxxxxxxxx> writes: >> And can you share the "linelength=" print out from simplefb ? > > Okay. Three cases, see below. > > Your patch tries to fix the stride, but what if it's the _depth_ > that's wrong ? Grub sets the mode, the pre-regression kernel picks this: > format=x8r8g8b8, mode=1024x768x32, linelength=4096 > Yes, it seems the VBE mode set by GRUB is x8r8g8b8. And the line length calculation is also correct: 1024 * (32 / 8) = 4096. > ========== Good ====================================================== > grub: gfxpayload=1024x768x24 > [ 0.003333] Console: colour dummy device 128x48 > [ 0.003333] printk: console [tty0] enabled > [ 0.417054] fbcon: Taking over console > [ 0.513399] pci 0000:01:05.0: vgaarb: setting as boot VGA device > [ 0.513431] pci 0000:01:05.0: vgaarb: bridge control possible > [ 0.513455] pci 0000:01:05.0: vgaarb: VGA device added: > decodes=io+mem,owns=io+mem,locks=none > [ 0.513490] vgaarb: loaded > [ 3.337529] simple-framebuffer simple-framebuffer.0: framebuffer at > 0xd8000000, 0x240000 bytes > [ 3.337567] simple-framebuffer simple-framebuffer.0: format=r8g8b8, > mode=1024x768x24, linelength=3072 This is also correct when GRUB sets it to r8g8b8, since the line length is: 1024 * (24 / 8) = 3072. > [ 3.338000] Console: switching to colour frame buffer device 128x48 > [ 3.566490] simple-framebuffer simple-framebuffer.0: fb0: simplefb > registered! > > ========== Bad after patch, typing blind to log in !================== > grub: gfxpayload=keep > [ 0.003333] Console: colour dummy device 128x48 > [ 0.003333] printk: console [tty0] enabled > [ 0.423925] fbcon: Taking over console > [ 0.520030] pci 0000:01:05.0: vgaarb: setting as boot VGA device > [ 0.520061] pci 0000:01:05.0: vgaarb: bridge control possible > [ 0.520085] pci 0000:01:05.0: vgaarb: VGA device added: > decodes=io+mem,owns=io+mem,locks=none > [ 0.520120] vgaarb: loaded > [ 3.290444] simple-framebuffer simple-framebuffer.0: framebuffer at > 0xd8000000, 0x240000 bytes > [ 3.290483] simple-framebuffer simple-framebuffer.0: format=r8g8b8, > mode=1024x768x24, linelength=3072 Now, this is the part where things start to break I believe. Because you mentioned before that gfxpayload=keep used to set the format to xr8g8b8 but now after my patch (and also after the original commit f35cd3fa7729) it is set to r8g8b8 instead. That *shouldn't* be an issue because it only means that the alpha channel is discarded but maybe it is an issue for your display controller? By the way, in https://www.panix.com/~pa/linux-6.3-simplefb/selected-modes that you shared before the gfxpayload=keep GRUB option used to also led to the pixel format being set to r8g8b8 instead of xr8g8b8. The difference is that in that output the line lenght didn't match the pixel format and size: [ 3.290596] simple-framebuffer simple-framebuffer.0: format=r8g8b8, mode=1024x768x24, linelength=4096 but after my patch you mentioned that is: [ 3.290483] simple-framebuffer simple-framebuffer.0: format=r8g8b8, mode=1024x768x24, linelength=3072 which at least matches, so in a way is an improvement (even when it still doesn't work). > [ 3.290916] Console: switching to colour frame buffer device 128x48 > [ 3.519523] simple-framebuffer simple-framebuffer.0: fb0: simplefb > registered! > > ========== Good, earlier kernel before regression ==================== > grub: gfxpayload=keep > [ 0.226675] Console: colour dummy device 128x48 > [ 0.228643] printk: console [tty0] enabled > [ 0.429214] fbcon: Taking over console > [ 0.524994] pci 0000:01:05.0: vgaarb: setting as boot VGA device > [ 0.525025] pci 0000:01:05.0: vgaarb: bridge control possible > [ 0.525049] pci 0000:01:05.0: vgaarb: VGA device added: > decodes=io+mem,owns=io+mem,locks=none > [ 0.525082] vgaarb: loaded > [ 3.320474] simple-framebuffer simple-framebuffer.0: framebuffer at > 0xd8000000, 0x300000 bytes > [ 3.320513] simple-framebuffer simple-framebuffer.0: format=x8r8g8b8, > mode=1024x768x32, linelength=4096 Yes, and it works because is the correct mode it seems but for some reason after commit f35cd3fa7729 the pixel format is calculated incorrectly. We can see that the total framebuffer size is 0x300000 bytes, which matches a 1024x768x34 mode framebuffer: 1024 * 768 * (34 / 8) = 3342336 = 0x300000. -- Best regards, Javier Martinez Canillas Core Platforms Red Hat
