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- From 7d40ea483850d1b5051773bbef01821b27272908 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 2/3] 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 3c197db42c9d..16e4a2e90fae 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
|
