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| author | Arvind Sankar <nivedita@alum.mit.edu> | 2020-03-19 22:00:25 -0400 |
|---|---|---|
| committer | Ard Biesheuvel <ardb@kernel.org> | 2020-04-23 20:15:06 +0200 |
| commit | fffb68047e563fb74f782c726e9bdf1fa117d93d (patch) | |
| tree | 6b699000c746ecac64a530049c82beaf49c37c27 /Documentation/fb | |
| parent | b4b89a02724245c4f4eda9dbfb7895ddf122ca7f (diff) | |
| download | linux-rt-fffb68047e563fb74f782c726e9bdf1fa117d93d.tar.gz | |
efi/gop: Allow specifying mode number on command line
Add the ability to choose a video mode for the selected gop by using a
command-line argument of the form
video=efifb:mode=<n>
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20200320020028.1936003-12-nivedita@alum.mit.edu
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Diffstat (limited to 'Documentation/fb')
| -rw-r--r-- | Documentation/fb/efifb.rst | 20 |
1 files changed, 17 insertions, 3 deletions
diff --git a/Documentation/fb/efifb.rst b/Documentation/fb/efifb.rst index 04840331a00e..367fbda2f4da 100644 --- a/Documentation/fb/efifb.rst +++ b/Documentation/fb/efifb.rst @@ -2,8 +2,10 @@ What is efifb? ============== -This is a generic EFI platform driver for Intel based Apple computers. -efifb is only for EFI booted Intel Macs. +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 ================== @@ -12,11 +14,14 @@ Supported Hardware - Macbook - Macbook Pro 15"/17" - MacMini +- ARM/ARM64/X86 systems with UEFI firmware How to use it? ============== -efifb does not have any kind of autodetection of your machine. +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 : @@ -28,6 +33,9 @@ You have to add the following kernel parameters in your elilo.conf:: 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: ======= =========================================================== @@ -36,4 +44,10 @@ nowc Don't map the framebuffer write combined. This can be used 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. + Edgar Hucek <gimli@dark-green.com> |