On 10/18/26 22:05, Helge Deller wrote: > On 10/15/26 11:07, Thomas Zimmermann wrote: >> This patch mangles fbcon output on fbdev HW drivers. It's >> reproducible on matroxfb and sisfb. Reverting the change restores >> these driver's functionality. > > Huh? > Are you sure? [...] > I don't see any specific issues with stifb.
Hi Helge, Thomas, I believe this is the regression I sent a fix for yesterday: https://lore.kernel.org/linux-fbdev/tyyp301mb1525c03fe71d47908263ebfcf6...@tyyp301mb1525.jpnp301.prod.outlook.com/ matroxfb and sisfb set FBINFO_HWACCEL_YPAN and start with yres_virtual larger than yres. With CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION=y, fbcon then scrolls by panning and draws text rows up to yres_virtual. bit_putcs() clips to var.yres, so it drops these rows. stifb does not set FBINFO_HWACCEL_YPAN, so fbcon uses SCROLL_MOVE there and never draws below var.yres, which is why it looks fine. The fix clips to GETVYRES() instead, so the bound from 3637d34b35b2 stays in place and the syzbot report should remain fixed. Thomas, could you test whether the patch fixes matroxfb and sisfb for you? Thanks, CatMe0w
