efi/gop: Allow specifying mode number on command line

[mirror_ubuntu-hirsute-kernel.git] / Documentation / fb / efifb.rst

diff --git a/Documentation/fb/efifb.rst b/Documentation/fb/efifb.rst
index 04840331a00e82d46276b1ce097dcbbb2ffe099f..367fbda2f4da72d7dacf536cf9234452b747eac2 100644 (file)
--- 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>