Difference between revisions of "VGA support"

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There are two kinds of VGA devices
+
== VGA initialization in coreboot ==
# on-board VGA
+
# add-on cards
+
  
= VGA initialization in coreboot v2 =
+
Since coreboot v4 you can configure VGA initialization in Kconfig. For older versions of coreboot check the history of this page.
  
== General ==
+
First do:
  
You need to enable two CONFIG options in your Mainboard Option.lb
+
<source lang="bash">
 +
$ make menuconfig
 +
</source>
  
  #VGA Console
+
Then go
  option CONFIG_CONSOLE_VGA=1
+
    Chipset  --->
  option CONFIG_PCI_ROM_RUN=1
+
      [*] Setup bridges on path to VGA adapter
 +
      [*] Run VGA option ROMs
 +
      Option ROM execution type (Native mode)  --->
  
'''CONFIG_PCI_ROM_RUN''' will use the embedded x86 emulator to run the BIOS image in the expansion ROM of a PCI device.
+
Alternatively you can choose the "Secure mode" to run the VGA option rom in a contained environment.
'''CONFIG_CONSOLE_VGA''' will redirect console messages to the VGA screen once VGA card is initialized.
+
  
For addon VGA cards, you don't have to do anything else besides these two CONFIG options.
+
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.
If your mainboard has an onboard VGA chip and you insert another VGA addon card, the addon
+
VGA card will be used instead of the onboard VGA chip.
+
  
== Onboard Video ==
+
=== 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  --->
 +
    [*] Add a VGA BIOS image
 +
    (oprom-0.rom) VGA BIOS path and filename
 +
    (8086,27a2) VGA device PCI IDs
  
1. In the mainboard Config.lb (./src/mainboard/<mfg>/<board>/Config.lb) You need to specify the device number for your onboard 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 [[bios_extract]].
  
==== How to compute the "rom_address" value ====
+
  $ git clone http://review.coreboot.org/p/bios_extract.git
ROM (called 'flash' a lot) chips are located directly below 4Gbyte (0xffffffff) boundary.
+
  
So you need to calculate the address by subtracting the
+
This is the most reliable way:
flash chip size (and adding the offset within the image)
+
* 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
  
In coreboot the offset within the image is 0, because its the first
+
Decompress your rom image with:
thing in the coreboot image.
+
$ ./bios_extract hdmag217.rom
  
So you need to compute the address in the systems memory space where the start of the video bios will show up.
+
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
  
To do this you take the 4Gb of address and subtract the size of your coreboot image.
+
then you have to cut the flash chip description off the image. In this case the BIOS image is 512KB, so you do
  0x100000000 - (ROM size in Kb * 1024)
+
  $ 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 can do this in bash by:
 
  
biossize=256
+
You will get an output similar to this:
printf "0x%x\n" $(( 0x100000000 - ($biossize*1024) ))
+
  
Addresses for popular chip sizes:
+
Using file "hdma.rom" (512kB)
  256K 0xfffc0000
+
Found Phoenix BIOS "Phoenix ServerBIOS 3 Release 6.0    "
  512k 0xfff80000
+
Version "DEVEL4E0", created on 03/20/06 at 14:37:39.
  1024k 0xfff00000
+
  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 [http://openbios.info/FCode_Suite FCode Suite]:
  
=== Target Configuration ===
+
$ 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
  
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.
+
Congratulations, that's your option rom (compare PCI IDs and Class Code to find it among the option roms).
  
in the normal section
+
=== Downloading ===
  
<source lang="bash">
+
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])
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.
+
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.
  
In the above example the bios chip is 512Kb part.  The video bios is  48Kb.  So (512*1024)-(48*1024) = 475136.
+
=== Extracting from the system (if everything else fails) ===
  
=== Creating an Image ===
+
However you might be able to retrieve your on-board video bios with Linux as well.
 
+
3. Finally, prepend your video bios to the coreboot.rom
+
  
 +
* 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
 +
<source lang="bash">cat /proc/iomem | grep 'Video ROM'</source>
 +
* From the command line enter:<br /><source lang="bash">dd if=/dev/mem of=vgabios.bin bs=1k count=64 skip=768</source> This assumes you card's bios is cached at 0xc0000, and is 64K long.
 +
<br /><source lang="bash">dd if=/dev/mem of=video.bios.bin.4 bs=65536 count=1 skip=12</source>
 +
This works for many of the VIA Epia boards.<br>
 +
Alternatively you can automatically generate it using this nice script from Peter Stuge:<br />
 
<source lang="bash">
 
<source lang="bash">
cat <videobios.bin> coreboot.rom > final_coreboot.rom
+
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])
 
</source>
 
</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.
 
 
dd is helpfull to get your <videobios.bin> when booted under the  factory BIOS.
 
 
 
== How to retrieve a good video bios ==
 
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])
 
 
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.
 
* From the command line enter:<br /><code>dd if=/dev/mem of=vgabios.bin skip=1536 count=128 or <br />dd if=/dev/mem of=vgabios.bin bs=1k count=64 skip=768<br />This assumes you card's bios is cached at 0xc0000, and is 64K long.  You<br />can see where and how much your card's bios is using by<br />doing a cat iomem | grep "Video ROM"<br /></code>
 
** dd Explained (man dd to learn more):
 
***  if is the location to retrieve from.
 
***  of is the output file (your rom image)
 
***  skip jumps n blocks where the default n is 512 bytes
 
***  count is how many blocks you wish to read
 
***  bs is the block size
 
 
* You now have a video bios image
 
* You now have a video bios image
 
=== Perl script to dump out your video bios ===
 
 
This is a simple script that computes the size and offset then uses
 
the command dd to dump your video bios to a file.
 
 
<source lang="perl">
 
#!/usr/bin/perl
 
 
($range, $info) = split /:/, `grep "Video ROM" /proc/iomem`;
 
($start, $end) = split /-/, $range;
 
 
if( $start eq "" ) {
 
        print "Couldn't find Video ROM in /proc/iomem\n";
 
        exit;
 
}
 
 
$offset = hex "0x$start";
 
$tmp = hex "0x$end";
 
$size = 1 + $tmp - $offset;
 
 
$command = "dd if=/dev/mem of=saved_vgabios.bin bs=1c count=$size skip=$offset";
 
print "range = $range, start = $start, size = $size\n";
 
print "$command\n";
 
system $command;
 
</source>
 

Revision as of 06:40, 4 December 2012

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.

$ git clone http://review.coreboot.org/p/bios_extract.git

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:

$ ./bios_extract hdmag217.rom

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