Difference between revisions of "VGA support"

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== VGA initialization in coreboot v2 (obsolete) ==
+
== VGA initialization in coreboot ==
  
=== General ===
+
Since coreboot v4 you can configure VGA initialization in Kconfig. For older versions of coreboot check the history of this page.
  
You need to enable two CONFIG options in your Mainboard Option.lb
+
First do:
  
 
<source lang="bash">
 
<source lang="bash">
# VGA Console
+
$ make menuconfig
option CONFIG_CONSOLE_VGA=1
+
option CONFIG_PCI_ROM_RUN=1
+
 
</source>
 
</source>
  
'''CONFIG_PCI_ROM_RUN''' will use the embedded x86 emulator to run the BIOS image in the expansion ROM of a PCI device.
+
Then go
'''CONFIG_CONSOLE_VGA''' will redirect console messages to the VGA screen once VGA card is initialized.
+
    Chipset  --->
 +
      [*] Setup bridges on path to VGA adapter
 +
      [*] Run VGA option ROMs
 +
      Option ROM execution type (Native mode)  --->
  
For add-on (PCI/PCIe/PCI-X/AGP) VGA cards, you don't have to do anything else besides these two CONFIG options.
+
Alternatively you can choose the "Secure mode" to run the VGA option rom in a contained environment.
If your mainboard has an on-board VGA chip and you insert another VGA add-on card, the add-on
+
 
VGA card will be used instead of the on-board VGA chip.
+
If you have no on-board graphics, you are done configuring coreboot at this point. You may exit configuration, and run make to get your VGA enabled coreboot image.
  
 
=== On-board Video Devices ===
 
=== On-board Video Devices ===
  
If you want to use the onboard VGA chip, you have to add the following options in addition to the CONFIG options described above.
+
If you run coreboot on a system with on-board graphics, you have to embed a VGA  on the top level, enter the file name of your option rom and the PCI ID of the associated graphics device in the form <vendor_id>,<device_id>:
  
==== Mainboard Configuration ====
+
    VGA BIOS  --->
'''Note:''' This step is not necessary for the VIA CN700 chipset.
+
    [*] Add a VGA BIOS image
 +
    (oprom-0.rom) VGA BIOS path and filename
 +
    (8086,27a2) VGA device PCI IDs
  
1. In the mainboard's Config.lb (./src/mainboard/<mfg>/<board>/Config.lb) You need to specify the device number for your on-board VGA and the address that the video bios will show up at in the system.
+
That's it, exit configuration, and run make to get your VGA enabled coreboot image.
  
<source lang = bash>
+
== How to retrieve a good video bios ==
device pci 9.0 on  # PCI
+
        chip drivers/pci/onboard
+
                device pci 9.0 on end
+
                register "rom_address" = "0xfff80000" #512k image
+
                #register "rom_address" = "0xfff00000" #1M image
+
        end
+
end
+
</source>
+
  
Replace the 9.0 with the dev.fn of your vga device.  You can find this number by doing a 'lspci' from the board booted under linux.
+
=== RECOMMENDED: Extracting from your vendor bios image ===
Please make sure the device number is correct. Otherwise the config code can not compute the proper ROM address.
+
  
 +
The recommended method is to take your mainboard vendor's BIOS image and extract the VGA BIOS using a tool called [http://cgit.freedesktop.org/~libv/bios_extract bios_extract].
  
===== How to compute the "rom_address" value =====
+
This is the most reliable way:
 +
* You are guaranteed to get an image that fits to your onboard VGA
 +
* Even if your VGA BIOS uses self-modifying code you get a correct image
  
ROM (called 'flash' a lot) chips are located directly below 4Gbyte  (0xffffffff) boundary.
+
Decompress your rom image with:
 +
<script lang="bash">
 +
$ ./bios_extract hdmag217.rom
 +
</script>
  
So you need to calculate the address by subtracting the
+
If bios_decode fails with a message like
flash chip size (and adding the offset within the image)
+
Using file "hdmag217.rom" (513kB)
 +
Found Phoenix BIOS "Phoenix ServerBIOS 3 Release 6.0    "
 +
Version "DEVEL4E0", created on 03/20/06 at 14:37:39.
 +
Error: Invalid module signature at 0x80581
  
In coreboot the offset within the image is 0, because its the first
+
then you have to cut the flash chip description off the image. In this case the BIOS image is 512KB, so you do
thing in the coreboot image.
+
$ dd if=hdmag217.rom of=hdma.rom bs=512k count=1
 +
1+0 records in
 +
1+0 records out
 +
524288 bytes transferred in 0.000883 secs (593688784 bytes/sec)
  
So you need to compute the address in the systems memory space where the start of the video bios will show up.
 
  
To do this you take the 4Gb of address and subtract the size of your coreboot image.
+
You will get an output similar to this:
0x100000000 - (ROM size in Kb * 1024)
+
  
You can do this in bash by:
+
Using file "hdma.rom" (512kB)
 +
Found Phoenix BIOS "Phoenix ServerBIOS 3 Release 6.0    "
 +
Version "DEVEL4E0", created on 03/20/06 at 14:37:39.
 +
0x715FC ( 27134 bytes)  ->  romexec_0.rom
 +
0x6E1CB ( 13338 bytes)  ->  strings_0.rom (29401 bytes)
 +
0x6D65D (  2899 bytes)  ->  display_0.rom (4128 bytes)
 +
0x6B62E (  8208 bytes)  ->  update_0.rom
 +
0x6B1E3 (  1072 bytes)  ->  decompcode_0.rom [0x5000:0xB6D0]
 +
0x6564F ( 23421 bytes)  ->  oprom_0.rom (36864 bytes)
 +
0x65608 (    44 bytes)  ->  tcpa_H_0.rom (32 bytes)
 +
0x65592 (    91 bytes)  ->  acpi_1.rom (116 bytes)
 +
0x65519 (    94 bytes)  ->  acpi_2.rom (244 bytes)
 +
0x654ED (    13 bytes)  ->  tcpa_*_0.rom
 +
0x64D4F (  1927 bytes)  ->  bioscode_0.rom (31382 bytes) [0xF000:0x856A]
 +
0x60020 ( 19728 bytes)  ->  romexec_1.rom
 +
0x570D9 ( 36656 bytes)  ->  oprom_1.rom (61440 bytes)
 +
0x4DB9D ( 38177 bytes)  ->  oprom_2.rom (63488 bytes)
 +
0x46493 ( 30447 bytes)  ->  oprom_3.rom (65536 bytes)
 +
0x41DAB ( 18125 bytes)  ->  logo_0.rom (310162 bytes)
 +
0x39CA5 ( 25439 bytes)  ->  oprom_4.rom (51200 bytes)
 +
0x36005 ( 15493 bytes)  ->  setup_0.rom (37682 bytes)
 +
0x325D7 ( 14867 bytes)  ->  template_0.rom (37728 bytes)
 +
0x2FA36 ( 11142 bytes)  ->  miser_0.rom (16208 bytes)
 +
0x2E63C (  5087 bytes)  ->  tcpa_Q_0.rom (16096 bytes)
 +
0x2D7C3 (  3678 bytes)  ->  acpi_0.rom (10464 bytes)
 +
0x1FA2A ( 41023 bytes)  ->  bioscode_1.rom (56080 bytes) [0xE000:0x40F0]
 +
0x14FE0 ( 43567 bytes)  ->  bioscode_2.rom (62416 bytes) [0x6000:0xCC30]
 +
0x0EB4C ( 25721 bytes)  ->  bioscode_3.rom (36976 bytes) [0x6000:0x3BC0]
 +
0x0D0A0 (  6801 bytes)  ->  bioscode_4.rom (31856 bytes) [0x5000:0xBF50]
  
<source lang="bash">
+
Now you can check the option roms (oprom_?.rom) with the tool romheaders which is part of the [http://openbios.info/FCode_Suite FCode Suite]:
biossize=256
+
printf "0x%x\n" $(( 0x100000000 - ($biossize*1024) ))
+
</source>
+
  
Addresses for popular chip sizes:
+
$ romheaders oprom_0.rom
  256K 0xfffc0000
+
  512k 0xfff80000
+
Image 1:
  1024k 0xfff00000
+
  PCI Expansion ROM Header:
 +
  Signature: 0x55aa (Ok)
 +
  CPU unique data: 0x48 0xeb 0x7b 0x01 0x76 0x00 0x00 0x00
 +
                    0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
 +
  Pointer to PCI Data Structure: 0x017c
 +
   
 +
  PCI Data Structure:
 +
  Signature: 0x50434952 'PCIR' (Ok)
 +
  Vendor ID: 0x1002
 +
  Device ID: 0x4752
 +
  Vital Product Data: 0x0000
 +
  PCI Data Structure Length: 0x0018 (24 bytes)
 +
  PCI Data Structure Revision: 0x00
 +
  Class Code: 0x030000 (VGA Display controller)
 +
  Image Length: 0x0048 blocks (36864 bytes)
 +
  Revision Level of Code/Data: 0x0421
 +
  Code Type: 0x00 (Intel x86)
 +
  Last-Image Flag: 0x80 (last image in rom)
 +
  Reserved: 0x0000
 +
   
 +
Platform specific data for x86 compliant option rom:
 +
  Initialization Size: 0x48 (36864 bytes)
 +
  Entry point for INIT function: 0x80
  
 +
Congratulations, that's your option rom (compare PCI IDs and Class Code to find it among the option roms).
  
==== Target Configuration ====
+
=== Downloading ===
  
2. You still need to modify your target 'Config.lb' to reserve space for the additional video bios. Reduce the size of your coreboot image by the size of the video bios. You will prepend the video bios to the coreboot image in step 3.
+
There are sites that have video bios roms on their website. (I know of this one for nvidia cards: [http://whitebunny.demon.nl/hardware/chipset_nvidia.html])
  
in the normal section
+
For Intel onboard graphics you can download the vbios(vga bios) from Intel's download section. The vbios is included with some versions of the graphics driver. The summary will say something like "NOTE:These materials are intended for use by developers.Includes VBIOS". The actual vbios file is the *.dat file included with the graphics driver.
  
<source lang="bash">
+
=== Extracting from the system (if everything else fails) ===
romimage "normal"
+
  # 48K for SCSI FW or ATI ROM
+
  option ROM_SIZE = 475136
+
</source>
+
 
+
or if you only have a "fallback" boot then use the "fallback" section instead.
+
 
+
In the above example the bios chip is 512Kb part.  The video bios is  48Kb.  So (512*1024)-(48*1024) = 475136.
+
 
+
'''Note:''' The Via CN700 chipset also requires legacy BIOS support.  This can be found or at http://bochs.sourceforge.net/ or in the Debian package bochsbios, filename /usr/share/bochs/BIOS-bochs-legacy.  You'll need to leave an additional 64k of space for the Bochs BIOS.
+
 
+
==== Creating an Image ====
+
 
+
3. Finally, prepend your video bios to the coreboot.rom
+
 
+
<source lang="bash">
+
cat videobios.bin coreboot.rom > final_coreboot.rom
+
</source>
+
 
+
where ''videobios.bin'' is the name of your video bios image.
+
You need to make sure the final_coreboot.rom size is the size of your ROM chip.  Normally 256kb, 512kb, or 1024Kb.
+
 
+
See below for instructions on how to retrieve the video BIOS from your factory ROM.
+
 
+
'''For Via CN700:'''
+
<source lang="bash">
+
cat videobios.bin bochsbios.bin coreboot.rom > final_coreboot.rom
+
</source>
+
 
+
== VGA initialization in coreboot v3 (obsolete) ==
+
 
+
In coreboot v3 you have to set your PCI option ROM execution method under the '''Device''' menu. The default is x86emu. To get a smaller (and slightly more insecure) version, you can switch to vm86. If you don't want option rom execution, set it to Disabled.
+
 
+
=== On-board devices ===
+
 
+
To add option roms for on-board video cards to your coreboot image, you can just add the image using lar:
+
 
+
<source lang="bash">
+
lar -C lzma -a coreboot.rom vgabios.rom:pciXXXX,YYYY.rom
+
</source>
+
 
+
In the above example, vgabios.rom is the name of your option rom on disk. XXXX is the PCI vendor ID of your on-board video adapter and YYYY is its PCI device ID.
+
 
+
== How to retrieve a good video bios ==
+
 
+
=== RECOMMENDED: Extracting from your vendor bios image ===
+
 
+
The recommended method is to take your mainboard vendor's BIOS image and extract the VGA BIOS using a tool called awardeco/amideco/phnxdeco. These tools are available in Debian/Ubuntu. If your vendor bios is award, you would use awardeco, if it's AMI amideco, and if it's Phoenix phnxdeco.
+
 
+
This is the most reliable way:
+
* You are guaranteed to get an image that fits to your onboard VGA
+
* Even if your VGA BIOS uses self-modifying code you get a correct image
+
With this method, you may need to pad the image to a certain size, e.g. 64k.  This is necessary at least for VIA CN700 chipsets where the factory VGA bios is smaller.
+
 
+
=== Downloading ===
+
 
+
There are sites that have video bios roms on their website. (I know of this one for nvidia cards: [http://whitebunny.demon.nl/hardware/chipset_nvidia.html])
+
  
=== Extracting from the system ===
+
However you might be able to retrieve your on-board video bios with Linux as well.
  
However you should be able to retrieve your own video bios as well with linux.
 
 
* Boot up a machine with a commercial bios (not coreboot) with the video card you wish to work under coreboot.
 
* Boot up a machine with a commercial bios (not coreboot) with the video card you wish to work under coreboot.
 
* You can see where and how much your card's bios is using by doing a  
 
* You can see where and how much your card's bios is using by doing a  
Line 145: Line 139:
 
Alternatively you can automatically generate it using this nice script from Peter Stuge:<br />
 
Alternatively you can automatically generate it using this nice script from Peter Stuge:<br />
 
<source lang="bash">
 
<source lang="bash">
$ cat /proc/iomem | grep 'Video ROM' | (read m; m=${m/ :*}; s=${m/-*}; e=${m/*-}; \
+
cat /proc/iomem | grep 'Video ROM' | (read m; m=${m/ :*}; s=${m/-*}; e=${m/*-}; \
$ dd if=/dev/mem of=vgabios.bin bs=1c skip=$[0x$s] count=$[$[0x$e]-$[0x$s]+1])
+
dd if=/dev/mem of=vgabios.bin bs=1c skip=$[0x$s] count=$[$[0x$e]-$[0x$s]+1])
 
</source>
 
</source>
 
* You now have a video bios image
 
* You now have a video bios image

Revision as of 21:04, 29 July 2011

VGA initialization in coreboot

Since coreboot v4 you can configure VGA initialization in Kconfig. For older versions of coreboot check the history of this page.

First do:

 $ make menuconfig

Then go

    Chipset  --->
     [*] Setup bridges on path to VGA adapter 
     [*] Run VGA option ROMs
     Option ROM execution type (Native mode)  --->

Alternatively you can choose the "Secure mode" to run the VGA option rom in a contained environment.

If you have no on-board graphics, you are done configuring coreboot at this point. You may exit configuration, and run make to get your VGA enabled coreboot image.

On-board Video Devices

If you run coreboot on a system with on-board graphics, you have to embed a VGA on the top level, enter the file name of your option rom and the PCI ID of the associated graphics device in the form <vendor_id>,<device_id>:

   VGA BIOS  --->
    [*] Add a VGA BIOS image
    (oprom-0.rom) VGA BIOS path and filename
    (8086,27a2) VGA device PCI IDs

That's it, exit configuration, and run make to get your VGA enabled coreboot image.

How to retrieve a good video bios

RECOMMENDED: Extracting from your vendor bios image

The recommended method is to take your mainboard vendor's BIOS image and extract the VGA BIOS using a tool called bios_extract.

This is the most reliable way:

  • You are guaranteed to get an image that fits to your onboard VGA
  • Even if your VGA BIOS uses self-modifying code you get a correct image

Decompress your rom image with: <script lang="bash"> $ ./bios_extract hdmag217.rom </script>

If bios_decode fails with a message like

Using file "hdmag217.rom" (513kB)
Found Phoenix BIOS "Phoenix ServerBIOS 3 Release 6.0     "
Version "DEVEL4E0", created on 03/20/06 at 14:37:39.
Error: Invalid module signature at 0x80581

then you have to cut the flash chip description off the image. In this case the BIOS image is 512KB, so you do

$ dd if=hdmag217.rom of=hdma.rom bs=512k count=1
1+0 records in
1+0 records out
524288 bytes transferred in 0.000883 secs (593688784 bytes/sec)


You will get an output similar to this:

Using file "hdma.rom" (512kB)
Found Phoenix BIOS "Phoenix ServerBIOS 3 Release 6.0     "
Version "DEVEL4E0", created on 03/20/06 at 14:37:39.
0x715FC ( 27134 bytes)   ->   romexec_0.rom
0x6E1CB ( 13338 bytes)   ->   strings_0.rom	(29401 bytes)
0x6D65D (  2899 bytes)   ->   display_0.rom	(4128 bytes)
0x6B62E (  8208 bytes)   ->   update_0.rom
0x6B1E3 (  1072 bytes)   ->   decompcode_0.rom			 [0x5000:0xB6D0]
0x6564F ( 23421 bytes)   ->   oprom_0.rom	(36864 bytes)
0x65608 (    44 bytes)   ->   tcpa_H_0.rom	(32 bytes)
0x65592 (    91 bytes)   ->   acpi_1.rom	(116 bytes)
0x65519 (    94 bytes)   ->   acpi_2.rom	(244 bytes)
0x654ED (    13 bytes)   ->   tcpa_*_0.rom
0x64D4F (  1927 bytes)   ->   bioscode_0.rom	(31382 bytes)	 [0xF000:0x856A]
0x60020 ( 19728 bytes)   ->   romexec_1.rom
0x570D9 ( 36656 bytes)   ->   oprom_1.rom	(61440 bytes)
0x4DB9D ( 38177 bytes)   ->   oprom_2.rom	(63488 bytes)
0x46493 ( 30447 bytes)   ->   oprom_3.rom	(65536 bytes)
0x41DAB ( 18125 bytes)   ->   logo_0.rom	(310162 bytes)
0x39CA5 ( 25439 bytes)   ->   oprom_4.rom	(51200 bytes)
0x36005 ( 15493 bytes)   ->   setup_0.rom	(37682 bytes)
0x325D7 ( 14867 bytes)   ->   template_0.rom	(37728 bytes)
0x2FA36 ( 11142 bytes)   ->   miser_0.rom	(16208 bytes)
0x2E63C (  5087 bytes)   ->   tcpa_Q_0.rom	(16096 bytes)
0x2D7C3 (  3678 bytes)   ->   acpi_0.rom	(10464 bytes)
0x1FA2A ( 41023 bytes)   ->   bioscode_1.rom	(56080 bytes)	 [0xE000:0x40F0]
0x14FE0 ( 43567 bytes)   ->   bioscode_2.rom	(62416 bytes)	 [0x6000:0xCC30]
0x0EB4C ( 25721 bytes)   ->   bioscode_3.rom	(36976 bytes)	 [0x6000:0x3BC0]
0x0D0A0 (  6801 bytes)   ->   bioscode_4.rom	(31856 bytes)	 [0x5000:0xBF50]

Now you can check the option roms (oprom_?.rom) with the tool romheaders which is part of the FCode Suite:

$ romheaders oprom_0.rom 

Image 1:
PCI Expansion ROM Header:
  Signature: 0x55aa (Ok)
  CPU unique data: 0x48 0xeb 0x7b 0x01 0x76 0x00 0x00 0x00
                   0x00 0x00 0x00 0x00 0x00 0x00 0x00 0x00
  Pointer to PCI Data Structure: 0x017c

PCI Data Structure:
  Signature: 0x50434952 'PCIR' (Ok)
  Vendor ID: 0x1002
  Device ID: 0x4752
  Vital Product Data:  0x0000
  PCI Data Structure Length: 0x0018 (24 bytes)
  PCI Data Structure Revision: 0x00
  Class Code: 0x030000 (VGA Display controller)
  Image Length: 0x0048 blocks (36864 bytes)
  Revision Level of Code/Data: 0x0421
  Code Type: 0x00 (Intel x86)
  Last-Image Flag: 0x80 (last image in rom)
  Reserved: 0x0000

Platform specific data for x86 compliant option rom:
  Initialization Size: 0x48 (36864 bytes)
  Entry point for INIT function: 0x80

Congratulations, that's your option rom (compare PCI IDs and Class Code to find it among the option roms).

Downloading

There are sites that have video bios roms on their website. (I know of this one for nvidia cards: [1])

For Intel onboard graphics you can download the vbios(vga bios) from Intel's download section. The vbios is included with some versions of the graphics driver. The summary will say something like "NOTE:These materials are intended for use by developers.Includes VBIOS". The actual vbios file is the *.dat file included with the graphics driver.

Extracting from the system (if everything else fails)

However you might be able to retrieve your on-board video bios with Linux as well.

  • Boot up a machine with a commercial bios (not coreboot) with the video card you wish to work under coreboot.
  • You can see where and how much your card's bios is using by doing a
cat /proc/iomem | grep 'Video ROM'
  • From the command line enter:
    dd if=/dev/mem of=vgabios.bin bs=1k count=64 skip=768
    This assumes you card's bios is cached at 0xc0000, and is 64K long.

dd if=/dev/mem of=video.bios.bin.4 bs=65536 count=1 skip=12

This works for many of the VIA Epia boards.
Alternatively you can automatically generate it using this nice script from Peter Stuge:

cat /proc/iomem | grep 'Video ROM' | (read m; m=${m/ :*}; s=${m/-*}; e=${m/*-}; \
dd if=/dev/mem of=vgabios.bin bs=1c skip=$[0x$s] count=$[$[0x$e]-$[0x$s]+1])
  • You now have a video bios image