This is a note to let you know that I've just added the patch titled vgacon: Record video mode changes with VT_RESIZEX to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: vgacon-record-video-mode-changes-with-vt_resizex.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From d4d0ad57b3865795c4cde2fb5094c594c2e8f469 Mon Sep 17 00:00:00 2001 From: "Maciej W. Rozycki" <macro@xxxxxxxxxxx> Date: Thu, 13 May 2021 11:51:41 +0200 Subject: vgacon: Record video mode changes with VT_RESIZEX From: Maciej W. Rozycki <macro@xxxxxxxxxxx> commit d4d0ad57b3865795c4cde2fb5094c594c2e8f469 upstream. Fix an issue with VGA console font size changes made after the initial video text mode has been changed with a user tool like `svgatextmode' calling the VT_RESIZEX ioctl. As it stands in that case the original screen geometry continues being used to validate further VT resizing. Consequently when the video adapter is firstly reprogrammed from the original say 80x25 text mode using a 9x16 character cell (720x400 pixel resolution) to say 80x37 text mode and the same character cell (720x592 pixel resolution), and secondly the CRTC character cell updated to 9x8 (by loading a suitable font with the KD_FONT_OP_SET request of the KDFONTOP ioctl), the VT geometry does not get further updated from 80x37 and only upper half of the screen is used for the VT, with the lower half showing rubbish corresponding to whatever happens to be there in the video memory that maps to that part of the screen. Of course the proportions change according to text mode geometries and font sizes chosen. Address the problem then, by updating the text mode geometry defaults rather than checking against them whenever the VT is resized via a user ioctl. Signed-off-by: Maciej W. Rozycki <macro@xxxxxxxxxxx> Fixes: e400b6ec4ede ("vt/vgacon: Check if screen resize request comes from userspace") Cc: stable@xxxxxxxxxxxxxxx # v2.6.24+ Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/video/console/vgacon.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) --- a/drivers/video/console/vgacon.c +++ b/drivers/video/console/vgacon.c @@ -1089,12 +1089,20 @@ static int vgacon_resize(struct vc_data if ((width << 1) * height > vga_vram_size) return -EINVAL; + if (user) { + /* + * Ho ho! Someone (svgatextmode, eh?) may have reprogrammed + * the video mode! Set the new defaults then and go away. + */ + screen_info.orig_video_cols = width; + screen_info.orig_video_lines = height; + vga_default_font_height = c->vc_font.height; + return 0; + } if (width % 2 || width > screen_info.orig_video_cols || height > (screen_info.orig_video_lines * vga_default_font_height)/ c->vc_font.height) - /* let svgatextmode tinker with video timings and - return success */ - return (user) ? 0 : -EINVAL; + return -EINVAL; if (con_is_visible(c) && !vga_is_gfx) /* who knows */ vgacon_doresize(c, width, height); Patches currently in stable-queue which might be from macro@xxxxxxxxxxx are queue-5.12/vgacon-record-video-mode-changes-with-vt_resizex.patch queue-5.12/vt-fix-character-height-handling-with-vt_resizex.patch queue-5.12/vt_ioctl-revert-vt_resizex-parameter-handling-removal.patch