diff options
Diffstat (limited to 'libre/linux-libre-rt/0002-drivers-firmware-skip-simpledrm-if-nvidia-drm.modese.patch')
| -rw-r--r-- | libre/linux-libre-rt/0002-drivers-firmware-skip-simpledrm-if-nvidia-drm.modese.patch | 89 |
1 files changed, 89 insertions, 0 deletions
diff --git a/libre/linux-libre-rt/0002-drivers-firmware-skip-simpledrm-if-nvidia-drm.modese.patch b/libre/linux-libre-rt/0002-drivers-firmware-skip-simpledrm-if-nvidia-drm.modese.patch new file mode 100644 index 000000000..f8a56fbe9 --- /dev/null +++ b/libre/linux-libre-rt/0002-drivers-firmware-skip-simpledrm-if-nvidia-drm.modese.patch @@ -0,0 +1,89 @@ +From ed37397be7fb48e57536a4e2ffe983569611a4cc Mon Sep 17 00:00:00 2001 +From: Javier Martinez Canillas <javierm@redhat.com> +Date: Thu, 19 May 2022 14:40:07 +0200 +Subject: [PATCH 2/5] drivers/firmware: skip simpledrm if nvidia-drm.modeset=1 + is set + +The Nvidia proprietary driver has some bugs that leads to issues if used +with the simpledrm driver. The most noticeable is that does not register +an emulated fbdev device. + +It just relies on a fbdev to be registered by another driver, that could +be that could be attached to the framebuffer console. On UEFI machines, +this is the efifb driver. + +This means that disabling the efifb driver will cause virtual consoles to +not be present in the system when using the Nvidia driver. Legacy BIOS is +not affected just because fbcon is not used there, but instead vgacon. + +Unless a VGA mode is specified using the vga= kernel command line option, +in that case the vesafb driver is used instead and its fbdev attached to +the fbcon. + +This is a problem because with CONFIG_SYSFB_SIMPLEFB=y, the sysfb platform +code attempts to register a "simple-framebuffer" platform device (that is +matched against simpledrm) and only registers either an "efi-framebuffer" +or "vesa-framebuffer" if this fails to be registered due the video modes +not being compatible. + +The Nvidia driver relying on another driver to register the fbdev is quite +fragile, since it can't really assume those will stick around. For example +there are patches posted to remove the EFI and VESA platform devices once +a real DRM or fbdev driver probes. + +But in any case, moving to a simpledrm + emulated fbdev only breaks this +assumption and causes users to not have VT if the Nvidia driver is used. + +So to prevent this, let's add a workaround and make the sysfb to skip the +"simple-framebuffer" registration when nvidia-drm.modeset=1 option is set. + +This is quite horrible, but honestly I can't think of any other approach. + +For this to work, the CONFIG_FB_EFI and CONFIG_FB_VESA config options must +be enabled besides CONFIG_DRM_SIMPLEDRM. + +Signed-off-by: Javier Martinez Canillas <javierm@redhat.com> +Cherry-picked-for: https://bugs.archlinux.org/task/73720 +--- + drivers/firmware/sysfb.c | 18 +++++++++++++++++- + 1 file changed, 17 insertions(+), 1 deletion(-) + +diff --git a/drivers/firmware/sysfb.c b/drivers/firmware/sysfb.c +index 82fcfd29bc4d..17b7e096b682 100644 +--- a/drivers/firmware/sysfb.c ++++ b/drivers/firmware/sysfb.c +@@ -34,6 +34,22 @@ + #include <linux/screen_info.h> + #include <linux/sysfb.h> + ++static int skip_simpledrm; ++ ++static int __init simpledrm_disable(char *opt) ++{ ++ if (!opt) ++ return -EINVAL; ++ ++ get_option(&opt, &skip_simpledrm); ++ ++ if (skip_simpledrm) ++ pr_info("The simpledrm driver will not be probed\n"); ++ ++ return 0; ++} ++early_param("nvidia-drm.modeset", simpledrm_disable); ++ + static struct platform_device *pd; + static DEFINE_MUTEX(disable_lock); + static bool disabled; +@@ -85,7 +101,7 @@ static __init int sysfb_init(void) + + /* try to create a simple-framebuffer device */ + compatible = sysfb_parse_mode(si, &mode); +- if (compatible) { ++ if (compatible && !skip_simpledrm) { + pd = sysfb_create_simplefb(si, &mode); + if (!IS_ERR(pd)) + goto unlock_mutex; +-- +2.43.0 + |