[coreboot] Intel G41 - Asrock G41M-GS: no coreboot screen output from Intel GPU on VGA

[h42 at memeware.net]

I dont get anything on the screen from coreboot. The later os is 
displaying fine.

How i build the image: ran on a fresh git cloned (from today) 'make 
menuconfig', chose just the mainboard manufacturer and the model, press 
esc, confirmed saving, ran 'make'. I installed this image and dont get 
any coreboot output on the screen. When i wait long enough, i get the 
output from the Linux OS on the screen.

 From the coreboot logfile:

coreboot-4.8-1195-gb75a08b199
[...]
FMAP: Found "FLASH" version 1.1 at 0.
FMAP: base = fff00000 size = 100000 #areas = 4
FMAP: area RW_MRC_CACHE found @ 10000 (65536 bytes)
MRC: No data in cbmem for 'RW_MRC_CACHE'.
BS: BS_DEV_ENUMERATE times (us): entry 0 run 150329 exit 16016
found VGA at PCI: 00:02.0
Setting up VGA for PCI: 00:02.0
Setting PCI_BRIDGE_CTL_VGA for bridge DOMAIN: 0000
Setting PCI_BRIDGE_CTL_VGA for bridge Root Device
Allocating resources...
Reading resources...
TOUUD 0x80000000 TOLUD 0x80000000 TOM 0x80000000
IGD decoded, subtracting 64M UMA and 4M GTT
TSEG decoded, subtracting 8M
Available memory below 4GB: 1972M
Adding UMA memory area base=0x7b400000 size=0x04c00000
Adding PCIe config bar base=0xe0000000 size=0x10000000
Done reading resources.
[...]
[21.707417] CONFIG =>
[21.709411]   (Primary   =>
[21.711924]      (Port => Analog  ,
[21.715130]       Framebuffer =>
[21.718076]         (Width     => 640,
[21.721542]          Height    => 400,
[21.725008]          Start_X   => 0,
[21.728301]          Start_Y   => 0,
[21.731594]          Stride    => 1,
[21.734886]          V_Stride  => 1,
[21.738179]          Tiling    => Linear ,
[21.741993]          Rotation  => No_Rotation,
[21.746153]          Offset => 0xffffffff,
[21.749966]          BPC    => 8),
[21.753085]       Mode =>
[21.755424]         (Dotclock           => 148500000,
[21.760192]          H_Visible          => 1920,
[21.764524]          H_Sync_Begin       => 2008,
[21.768857]          H_Sync_End         => 2052,
[21.773190]          H_Total            => 2200,
[21.777523]          V_Visible          => 1080,
[21.781857]          V_Sync_Begin       => 1084,
[21.786189]          V_Sync_End         => 1089,
[21.790522]          V_Total            => 1125,
[21.794855]          H_Sync_Active_High => True,
[21.799189]          V_Sync_Active_High => True,
[21.803521]          BPC                => 5)),
[21.807767]    Secondary =>
[21.810281]      (Port => Disabled,
[21.813487]       Framebuffer =>
[21.816433]         (Width     => 1,
[21.819727]          Height    => 1,
[21.823020]          Start_X   => 0,
[21.826313]          Start_Y   => 0,
[21.829605]          Stride    => 1,
[21.832899]          V_Stride  => 1,
[21.836193]          Tiling    => Linear ,
[21.840006]          Rotation  => No_Rotation,
[21.844166]          Offset => 0x00000000,
[21.847979]          BPC    => 8),
[21.851098]       Mode =>
[21.853438]         (Dotclock           => 24000000,
[21.858118]          H_Visible          => 1,
[21.862191]          H_Sync_Begin       => 1,
[21.866263]          H_Sync_End         => 1,
[21.870336]          H_Total            => 1,
[21.874409]          V_Visible          => 1,
[21.878482]          V_Sync_Begin       => 1,
[21.882555]          V_Sync_End         => 1,
[21.886629]          V_Total            => 1,
[21.890702]          H_Sync_Active_High => False,
[21.895121]          V_Sync_Active_High => False,
[21.899541]          BPC                => 5)),
[21.903787]    Tertiary  =>
[21.906300]      (Port => Disabled,
[21.909507]       Framebuffer =>
[21.912453]         (Width     => 1,
[21.915746]          Height    => 1,
[21.919039]          Start_X   => 0,
[21.922331]          Start_Y   => 0,
[21.925624]          Stride    => 1,
[21.928918]          V_Stride  => 1,
[21.932211]          Tiling    => Linear ,
[21.936023]          Rotation  => No_Rotation,
[21.940183]          Offset => 0x00000000,
[21.943996]          BPC    => 8),
[21.947116]       Mode =>
[21.949455]         (Dotclock           => 24000000,
[21.954135]          H_Visible          => 1,
[21.958207]          H_Sync_Begin       => 1,
[21.962280]          H_Sync_End         => 1,
[21.966353]          H_Total            => 1,
[21.970427]          V_Visible          => 1,
[21.974499]          V_Sync_Begin       => 1,
[21.978572]          V_Sync_End         => 1,
[21.982646]          V_Total            => 1,
[21.986719]          H_Sync_Active_High => False,
[21.991138]          V_Sync_Active_High => False,
[21.995557]          BPC                => 5)));
PCI: 00:02.0 init finished in 307222 usecs
PCI: 00:02.1 init ...
PCI: 00:02.1 init finished in 2009 usecs
PCI: 00:1b.0 init ...
[...]



So it seems to have detected that my screen is 1920*1080. GPU + screen 
detection seems to be working. But i dont get any coreboot output on the 
screen.
The output had worked fine on this screen with the OEM BIOS.