uvesafb: the driver core
uvesafb is an enhanced version of vesafb. It uses a userspace helper (v86d)
to execute calls to the x86 Video BIOS functions. The driver is not limited
to any specific arch and whether it works on a given arch or not depends on
that arch being supported by the userspace daemon. It has been tested on
x86_32 and x86_64.
A single BIOS call is represented by an instance of the uvesafb_ktask
structure. This structure contains a buffer, a completion struct and a
uvesafb_task substructure, containing the values of the x86 registers, a flags
field and a field indicating the length of the buffer. Whenever a BIOS call
is made in the driver, uvesafb_exec() builds a message using the uvesafb_task
substructure and the contents of the buffer. This message is then assigned a
random ack number and sent to the userspace daemon using the connector
interface.
The message's sequence number is used as an index for the uvfb_tasks array,
which provides a mapping from the messages coming from userspace to the
in-kernel uvesafb_ktask structs.
The userspace daemon performs the requested operation and sends a reply in the
form of a uvesafb_task struct and, optionally, a buffer. The seq and ack
numbers in the reply should be exactly the same as those in the request.
Each message from userspace is processed by uvesafb_cn_callback() and after
passing a few sanity checks leads to the completion of a BIOS call request.
Signed-off-by: Michal Januszewski <spock@gentoo.org>
Signed-off-by: Antonino Daplas <adaplas@gmail.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Paulo Marques <pmarques@grupopie.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 5216c11..f1cc899 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -592,6 +592,24 @@
Say Y if you have one of those.
+config FB_UVESA
+ tristate "Userspace VESA VGA graphics support"
+ depends on FB && CONNECTOR
+ select FB_CFB_FILLRECT
+ select FB_CFB_COPYAREA
+ select FB_CFB_IMAGEBLIT
+ select FB_MODE_HELPERS
+ help
+ This is the frame buffer driver for generic VBE 2.0 compliant
+ graphic cards. It can also take advantage of VBE 3.0 features,
+ such as refresh rate adjustment.
+
+ This driver generally provides more features than vesafb but
+ requires a userspace helper application called 'v86d'. See
+ <file:Documentation/fb/uvesafb.txt> for more information.
+
+ If unsure, say N.
+
config FB_VESA
bool "VESA VGA graphics support"
depends on (FB = y) && X86