Since its introduction in 2009, the vesa.ko kernel module contains a bug, presumably of the category "use of uninitialized data structures".
This bug prevents the system resuming correctly on systems with nvidia graphics card and using the sc console in text mode.
To build+install a custom kernel without vesa kernel module is the easiest workaround I know to make resuming after S3 suspend ("
Fixing the bug would require just two lines of code.
However, I am afraid I do not get the wording right, miss out some important detail etc.
I already made a PR in 2017.
However, my original interpretation of the bug was incorrect, as the very detailed technical discussion that followed revealed.
So this distraction/confusion might have contributed to the inaction following my PR.
So I kindly ask you for your assistance.
I want to make sure that this bug gets fixed and I do no longer need to build custom kernels, only to have suspend/resume work with my Nvidia cards.
Please tell me what I should add/leave out to the PR draft below.
Thank you very much for any suggestion or advice!
This bug prevents the system resuming correctly on systems with nvidia graphics card and using the sc console in text mode.
To build+install a custom kernel without vesa kernel module is the easiest workaround I know to make resuming after S3 suspend ("
zzz
") succeed.Fixing the bug would require just two lines of code.
However, I am afraid I do not get the wording right, miss out some important detail etc.
I already made a PR in 2017.
However, my original interpretation of the bug was incorrect, as the very detailed technical discussion that followed revealed.
So this distraction/confusion might have contributed to the inaction following my PR.
So I kindly ask you for your assistance.
I want to make sure that this bug gets fixed and I do no longer need to build custom kernels, only to have suspend/resume work with my Nvidia cards.
Please tell me what I should add/leave out to the PR draft below.
Title draft said:vesa.ko: Invalid BIOS call when resuming from S3 suspend/sleep causes nvidia driver hang
Extra information in the bugs' page said:OS Version: all (is this correct? all versions since the introduction of vesa.ko are affected, e.g. all since 2009)
Ports/Packages: Kernel (is this correct? or do I have to enter port/package xorg?)
Platform: amd64 (there is reason to assume i386 is affected too, but didn't test)
Users affected: Many (e.g. all users who use nvidia card/driver and would like to use sleep/S3 suspend)
Text draft said:In vesa.ko there is a function that gets called when resuming from sleep, e.g. at resuming after S3 suspend via 'zzz'.
This function does a BIOS call, which is related to restoring the graphics cards' previous state it had before powering off.
On Nvidia cards this BIOS function seems to be implemented in a different way than on most other cards.
For this reason, calling this BIOS function causes the Nvidia graphics driver to hang, failing to resume.
(For technical background, read my discussion with jkim in PR 224069: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=224069 )
Reproducing the bug is easy:
-Install FreeBSD (eg using GENERIC kernel).
-Enable sc (kern.vty="sc" in /boot/loader.conf).
-Install xorg. Install and configure nvidia driver. Reboot and start xorg via startx.
-Enter "zzz" in a xterm.
-Watch the system/driver hang, keyboard (PS/2) and mouse becoming unresponsive when attempting to switch back to graphics mode.
-Hitting the power button results no visible change, until after timeout a message about an unresponsive stop job (presumably the nvidia driver) appears shortly before powering off.
For reproducing the bug it is essential to use GENERIC kernel!
Because, working around by building and installing a custom kernel without "options VESA" fixes the hang after suspend/resume. It is also important to not have vt and its helper modules (vt_efifb etc) in the kernel, as these pull in the vesa.ko showstopper module.
Already back in 2017 I found that skipping (commenting out) the Nvidia BIOS call fixes the issue, making resume work reliably.
So I believe the proper fix would be:
1. check whether the graphics card is Nvidia
2. if it is Nvidia, skip that BIOS call in /usr/src/sys/dev/fb/vesa.c line 520.
Pseudocode for a patch might look like this:
(+)if (! nvidia_card_is_installed) {
x86bios_intr(®s, 0x10);
(+)}
Side note:
All my systems use the sc console, not the vt console.
So I do not know the system behaviour when using vt.
Thus please use sc in text mode when reproducing the bug!
Thank you very much for any suggestion or advice!
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