November 2023 - openSUSE Kernel - openSUSE Mailing Lists

Disabling /dev/fb0 on TW
by Thomas Zimmermann 06 Feb '25

06 Feb '25

tl;dr: Disable fbdev userspace interfaces on TW Hi, the upcoming Linux kernel v6.6 will contain the option to disable fbdev userspace interfaces in the kernel configuration. [1] I intent to enable this and thereby switch off /dev/fb0 et al. The tracker bug is boo#1212947. [2] * Why? The old fbdev subsystem is an endless source of bugs. For example, we recently had an out-of-bounds access in the fbdev emulation, where userspace could write beyond the end of the framebuffer memory. [3] Fbdev is under-maintained. I've been doing improvements in recent kernel releases, but only where it benefits the DRM subsystem. Disabling fbdev userspace interfaces will also help weeding out any programs that still contain hard dependencies on them. * What changes? Enabling the new kernel option disables all fbdev userspace interfaces. These are * the device files, such as /dev/fb0 * the sys files under /sys/class/graphics/fb[0-9]+ * /proc/fb * What are the effects on userspace programs? Userspace applications run on the desktop via Wayland or X. There will be no change to them. Xorg and Wayland compositors run on DRM interfaces. A few programs run on SDL, which has no dependency on fbdev either. Any fbdev support in these mid-layer components should be disabled as well. There's one known affected program: TW's text-mode installer can use the tool fbiterm to display CJK symbols during installation. This comes from a time when some low-end systems where not able to boot graphics installation. fbiterm has been unmaintained for >15 years and is ready for retirement. But there's no good drop-in replacement. I propose to simply remove fbiterm and let the graphics installer handle CJK. * What about the framebuffer console? The kernel-provided framebuffer console does not change. The kernel will still show the regular console. Userspace interfaces in /sys/class/graphics/fbcon are still available. For questions and discussion, please comment here or in boo#1212947. Best regards Thomas [1] https://elixir.bootlin.com/linux/v6.6-rc1/source/drivers/video/fbdev/core/K… [2] https://bugzilla.opensuse.org/show_bug.cgi?id=1212947 [3] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?… -- Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Frankenstrasse 146, 90461 Nuernberg, Germany GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman HRB 36809 (AG Nuernberg)

2 6

[opensuse-kernel] kernel-default-base-2.6.29-5.2.x86_64 rpm errors
by Dave Plater 18 Jul '24

18 Jul '24

Hi, I'm busy updating to the latest factory kernel and have received the following errors from kernel-default-base installation (I did insert a blank dvd during the installation of the rpm by zypper):- WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sd_mod.ko needs unknown symbol crc_t10dif WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol register_cdrom WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol cdrom_ioctl WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol cdrom_media_changed WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol cdrom_get_media_event WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol cdrom_release WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol cdrom_open WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol unregister_cdrom WARNING: /lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sr_mod.ko needs unknown symbol cdrom_number_of_slots And then these errors which I think IIRC happened before when the kernel was first split into three:- Kernel image: /boot/vmlinuz-2.6.29-rc8-5-default Initrd image: /boot/initrd-2.6.29-rc8-5-default Root device: /dev/disk/by-id/ata-WDC_WD800JB-00JJC0_WD-WMAM9RA78067-part3 (/dev/sda3) (mounted on / as xfs) Resume device: /dev/disk/by-id/ata-WDC_WD800JB-00JJC0_WD-WMAM9RA78067-part2 (/dev/sda2) FATAL: Module processor not found. WARNING: no dependencies for kernel module 'processor' found. FATAL: Module thermal not found. WARNING: no dependencies for kernel module 'thermal' found. FATAL: Module ata_generic not found. WARNING: no dependencies for kernel module 'ata_generic' found. FATAL: Module piix not found. WARNING: no dependencies for kernel module 'piix' found. FATAL: Module ide_pci_generic not found. WARNING: no dependencies for kernel module 'ide_pci_generic' found. FATAL: Module fan not found. WARNING: no dependencies for kernel module 'fan' found. FATAL: Module xfs not found. WARNING: no dependencies for kernel module 'xfs' found. FATAL: Module usbhid not found. WARNING: no dependencies for kernel module 'usbhid' found. Kernel Modules: scsi_mod libata ata_piix edd ahci sd_mod usbcore ohci-hcd ehci-hcd uhci-hcd WARNING: /dev/shm/mkinitramfs.0drQsZ/mnt/lib/modules/2.6.29-rc8-5-default/kernel/drivers/scsi/sd_mod.ko needs unknown symbol crc_t10dif Features: block usb resume.userspace resume.kernel Bootsplash: openSUSE (1280x1024) 22669 blocks Should I open a bug report about the errors which are possibly from inserting a dvd while the kernel rpm was installing? Regards Dave P -- To unsubscribe, e-mail: opensuse-kernel+unsubscribe(a)opensuse.org For additional commands, e-mail: opensuse-kernel+help(a)opensuse.org

2 2

Re: Disabling /dev/fb0 on TW
by Michal Suchánek 14 Nov '23

14 Nov '23

On Tue, Oct 10, 2023 at 10:35:53AM +0200, Jan Engelhardt wrote: > > On Tuesday 2023-10-10 10:26, Thomas Zimmermann via openSUSE Factory wrote: > > fbiterm has been unmaintained for >15 years > > 8 years give or take; https://github.com/jengelh/fbterm/commits/master > > > But there's no good drop-in replacement. > > kmscon. > > $ cat /etc/kmscon/kmscon.conf > font-name=Consoleet VGA 9x16 > font-size=32 > > (systemctl enable kmsconvt@tty2) > > It even does CJK (which is what fb(i)term was previously used for). It does not, however, use the kernel keymap, and does not support changing the keymap on the fly which is something the installer abuses. There is an laternative that does support this: mlterm-sdl. It is a hassle to set up, though. And nobody cared to create and test the setup for the installer to use mlterm instead of fbiterm. Thanks Michal

1 0