[SeaBIOS] [PATCH] Enable VGA output when setting Cirrus-specific mode
Laszlo Ersek
lersek at redhat.com
Thu Feb 14 05:43:32 CET 2013
This patch does the same for Cirrus as David's following patch for bochs,
originally posted under
<http://www.seabios.org/pipermail/seabios/2013-February/005434.html>:
Enable VGA output when settings bochs-specific mode
When used from OVMF+CSM, we got no video output. It appears that we were
never enabling the display output except when configuring a text mode.
Which never happens, in the OVMF+CSM case.
In my testing on RHEL-6.3 with OVMF -D CSM_ENABLE / CONFIG_CSM bios.bin /
CONFIG_QEMU vgabios.bin, using Cirrus, VESA mode 0x115 is selected (Direct
Color, 800x600x24).
According to <http://www.osdever.net/FreeVGA/vga/attrreg.htm>,
cirrus_switch_mode()
stdvga_attr_mask()
currently keeps/sets the "Attribute Controller Graphics Enable" bit set in
the "Attribute Mode Control Register". When invoked from OVMF+CSM, that is
not enough however, so let's do the same as for Bochs:
stdvga_attrindex_write(0x20);
which corresponds to setting the "Palette Address Source" bit in the
"Attribute Address Register":
"This bit is set to 0 to load color values to the registers in the
internal palette. It is set to 1 for normal operation of the attribute
controller. [...]"
clext_set_mode()
stdvga_set_mode() -- for regular modes
stdvga_attrindex_write() -- existing call
cirrus_switch_mode() -- for Cirrus modes
stdvga_attrindex_write() -- call added by this patch
Signed-off-by: Laszlo Ersek <lersek at redhat.com>
---
My motivation for using Cirrus instead of stdvga is three-fold:
- using libvirt on RHEL-6.3, Cirrus seems to be the default video card
for the guests I tend to create,
- it provides better max resolution in the Fedora 18 guest,
- for some reason (maybe due to kernel build options?) the Fedora 18
guest can't display character mode consoles on stdvga, but works well
with Cirrus. (F18/Xorg/{stdvga,cirrus} are OK, and so are
RHEL6/{Xorg,console}/{stdvga,cirrus}.)
Tested with RHEL-6, Fedora 18, and Windows 8 Consumer Preview.
vgasrc/clext.c | 1 +
1 files changed, 1 insertions(+), 0 deletions(-)
diff --git a/vgasrc/clext.c b/vgasrc/clext.c
index dd45df3..d02b880 100644
--- a/vgasrc/clext.c
+++ b/vgasrc/clext.c
@@ -433,6 +433,7 @@ cirrus_switch_mode(struct cirrus_mode_s *table)
else if (memmodel != MM_TEXT)
on = 0x01;
stdvga_attr_mask(0x10, 0x01, on);
+ stdvga_attrindex_write(0x20);
}
static void
--
1.7.1
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