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| author | Breno Leitao <leitao@debian.org> | 2026-08-05 07:52:36 -0700 |
|---|---|---|
| committer | Tejun Heo <tj@kernel.org> | 2026-08-10 11:47:20 -1000 |
| commit | a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656 (patch) | |
| tree | 39f5b258386e1127d253d293194e9a2991bf3c34 /Documentation/fb/efifb.rst | |
| download | linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.tar.gz linux-stable-a5bde5d8fde8a8cb28e59a672d5ddc5b9c1e7656.zip | |
workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted
apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.
No functional change: only unbound workqueues reach apply_wqattrs_*()
today.
Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'Documentation/fb/efifb.rst')
| -rw-r--r-- | Documentation/fb/efifb.rst | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/Documentation/fb/efifb.rst b/Documentation/fb/efifb.rst new file mode 100644 index 000000000..3d4aab406 --- /dev/null +++ b/Documentation/fb/efifb.rst @@ -0,0 +1,71 @@ +=================================== +efifb - Generic EFI platform driver +=================================== + +This is a generic EFI platform driver for systems with UEFI firmware. The +system must be booted via the EFI stub for this to be usable. efifb supports +both firmware with Graphics Output Protocol (GOP) displays as well as older +systems with only Universal Graphics Adapter (UGA) displays. + +Supported Hardware +================== + +- iMac 17"/20" +- Macbook +- Macbook Pro 15"/17" +- MacMini +- ARM/ARM64/X86 systems with UEFI firmware + +How to use it? +============== + +For UGA displays, efifb does not have any kind of autodetection of your +machine. + +You have to add the following kernel parameters in your elilo.conf:: + + Macbook : + video=efifb:macbook + MacMini : + video=efifb:mini + Macbook Pro 15", iMac 17" : + video=efifb:i17 + Macbook Pro 17", iMac 20" : + video=efifb:i20 + +For GOP displays, efifb can autodetect the display's resolution and framebuffer +address, so these should work out of the box without any special parameters. + +Accepted options: + +======= =========================================================== +nowc Don't map the framebuffer write combined. This can be used + to workaround side-effects and slowdowns on other CPU cores + when large amounts of console data are written. +======= =========================================================== + +Options for GOP displays: + +mode=n + The EFI stub will set the mode of the display to mode number n if + possible. + +<xres>x<yres>[-(rgb|bgr|<bpp>)] + The EFI stub will search for a display mode that matches the specified + horizontal and vertical resolution, and optionally bit depth, and set + the mode of the display to it if one is found. The bit depth can either + "rgb" or "bgr" to match specifically those pixel formats, or a number + for a mode with matching bits per pixel. + +auto + The EFI stub will choose the mode with the highest resolution (product + of horizontal and vertical resolution). If there are multiple modes + with the highest resolution, it will choose one with the highest color + depth. + +list + The EFI stub will list out all the display modes that are available. A + specific mode can then be chosen using one of the above options for the + next boot. + +Edgar Hucek <gimli@dark-green.com> |
