Graphics Mode

[galla rao]

Video Mode in Coreboot

*CorebootLog*
coreboot video frame buffer information
physical_address: 0xC0000000
*x_resolution: 0x400*
*y_resolution: 0x300*
bits_per_pixel: 0x20
bytes_per_line: 0x1000
red_mask_size: 0x8
red_mask_pos: 0x10

GOP UEFI driver (Tiano payload) is expected to report 4 modes
GOP should report MaxMode 4 *0:
1600x900 BGRReserved Pixels 1600 1:
640x480 BGRReserved Pixels 640 2:
800x600 BGRReserved Pixels 800 3:
1024x768 BGRReserved Pixels 1024

In BayTrail Platform i only see 1 single mode which is 400 * 300

what changes are expected from GOP/VBIOS  to set one of the 4 graphics mode
Please advise!

Best Regards
Ranga

[Matt DeVillier]

hello Ranga,

what method and setting do you have selected for graphics init?
400x300 would indicate that coreboot is initializing the display in
VGA text mode, rather than a VESA framebuffer mode - you likely need
to change this in Kconfig.  The Tianocore coreboot framebuffer GOP
driver can only reuse whatever framebuffer coreboot has set up, so
there will only ever be one option available. Assuming you are running
a VGA Option ROM, you're going to be limited to VGA text mode or
640x480, 800x600, 1024x768, or 1280x1024 (at various bit depths).
1600x900 isn't going to be available, I don't believe.

cheers,
Matt

On Thu, Jan 3, 2019 at 2:25 AM galla rao  wrote:
> Video Mode in Coreboot
>
> CorebootLog
> coreboot video frame buffer information
> physical_address: 0xC0000000
> x_resolution: 0x400
> y_resolution: 0x300
> bits_per_pixel: 0x20
> bytes_per_line: 0x1000
> red_mask_size: 0x8
> red_mask_pos: 0x10
>
> GOP UEFI driver (Tiano payload) is expected to report 4 modes
> GOP should report MaxMode 4 *0:
> 1600x900 BGRReserved Pixels 1600 1:
> 640x480 BGRReserved Pixels 640 2:
> 800x600 BGRReserved Pixels 800 3:
> 1024x768 BGRReserved Pixels 1024
>
> In BayTrail Platform i only see 1 single mode which is 400 * 300
>
> what changes are expected from GOP/VBIOS  to set one of the 4 graphics mode
> Please advise!
>
> Best Regards
> Ranga
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[Nico Huber]

Hi Ranga,

On 03.01.19 09:24, galla rao wrote:
> Video Mode in Coreboot
>
> *CorebootLog*
> coreboot video frame buffer information
> physical_address: 0xC0000000
> *x_resolution: 0x400*
> *y_resolution: 0x300*

0x400 x 0x300 is exactly 1024x768.
> bits_per_pixel: 0x20
> bytes_per_line: 0x1000
> red_mask_size: 0x8
> red_mask_pos: 0x10
>
> GOP UEFI driver (Tiano payload) is expected to report 4 modes
> GOP should report MaxMode 4 *0:
> 1600x900 BGRReserved Pixels 1600 1:
> 640x480 BGRReserved Pixels 640 2:
> 800x600 BGRReserved Pixels 800 3:
> 1024x768 BGRReserved Pixels 1024

Unlike legacy firmware, coreboot doesn't stay active after handing
execution over to its payload. So there is no coreboot code that
could change to a different mode afterwards. If you have to switch
modes in Tianocore, you should disable the coreboot framebuffer and
add a GOP driver to Tianocore instead.

With open-source graphics init, you could also set a fixed mode in
coreboot. Alas, there is no open-source solution for Bay Trail that
I know of. Though, existing solutions (e.g. libgfxinit) for other
Intel platforms could be extended for Bay Trail (and could also be
used to write an open-source GOP driver).

Nico