On Sun, Mar 17, 2019 at 06:24:57AM +0800, Yifeng Li wrote: > On a Thinkpad s30 (Pentium III / i440MX, Lynx3DM), rebooting with > sm712fb framebuffer driver would cause a white screen of death on > the next POST, presumably the proper timings for the LCD panel was > not reprogrammed properly by the BIOS. > > Experiments showed a few CRTC Scratch Registers, including CRT3D, > CRT3E and CRT3F may be used internally by BIOS as some flags. CRT3B is > a hardware testing register, we shouldn't mess with it. CRT3C has > blanking signal and line compare control, which is not needed for this > driver. > > Stop writing to CR3B-CR3F (a.k.a CRT3B-CRT3F) registers. Even if these > registers don't have side-effect on other systems, writing to them is > also highly questionable. > > Signed-off-by: Yifeng Li <tomli@xxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx # v4.4+ Tested-by: Sudip Mukherjee <sudipm.mukherjee@xxxxxxxxx> -- Regards Sudip
