hybrid-graphics-linux team mailing list archive

[Matthias Fulz <olz1983@xxxxxxxxxxxxxx>]

On 07/19/2010 02:33 PM, Ruslan N. Marchenko wrote:
> On Mon, 19 Jul 2010, Matthias Fulz wrote:
>> Coutld it be perhaps, that the VGA ROM is directly mapped to the address
>> by the System Bios?
>>
>> Perhaps its not even a real RAM Array, instead it's a RAM address which
>> leads to the VGA ROM?
>>
>> Any way to read this address under windows?
>> Perhaps the BIOS is remapping the ATI BIOS to the address under windows,
>> I would check it, if anyone knows a way to read the addresses under
>> windows.
> Debugger? Will try at home, though consider the fact that vanilla
> catalyst from ati is not able to work with switchable graphics either,
> you need to have installed OEM version of driver (from acer in my case)
> which can afterwards be upgraded with vendor's driver.
> 

Perfect give feedback ;)

>>
>>
>> And here is (I think the problem we have with the RO MEM Array):
>>
>> http://www.pcguide.com/ref/ram/umaMap-c.html
>> http://www.pcguide.com/ref/ram/umaShadowing-c.html
>>
>> So I think we need to find a way to bypass the BIOS Shadowing.
>> Best would be to do it (if possible) inside the Linux Kernel.
>>
> At first i think we need to confirm whether we really need it. I.e. the
> problem we're trying to solve with this - to use catalyst drivers. Now,
> fglrx Xorg driver is not able to load bios, which can be caused by -
> a) it is dumb and just tries to read bios via /dev/mem which is intel vga
> b) it fetches bios correctly but unable to parse it because of
> modifications done by oem manufacturer
> c) something else?
> 
> Bioses differs with only 3 bytes - is there any checksum for integrity
> verification? even one byte difference should change the whole checksum
> field, given it exists.
> 

For me it differs in more then 3 Bytes here is the cmp of my discrete
bios and hybrid bios from the ati card:

cmp -l atibios_hybrid atibios_single
   34 321 156
  456 175 300
44361   0  46
44362   0  33
44363   0 126
44364   0   5
44365   0 144
44368   0   3
44369   0  26
44371   0  60
44373   0  40
44375   0   3
44377   0   6
44385   2   6
44386   0   2
44388  74   0
44417   0   1
44500 141 101
45081   0   3