[Qemu-devel] Re: [PATCH] Don't explicitly set BAR values for VMware VGA

[Anthony Liguori <aliguori@us.ibm.com>]

andrzej zaborowski wrote:
> On 22/02/2008, Anthony Liguori <aliguori@us.ibm.com> wrote:
>   
>> Right now we set explict base addresses for the PCI IO regions in the VMware
>>  VGA device.  We don't register the second region at all and instead directly
>>  map the physical memory.
>>
>>  The problem is, the addresses we're setting in the BAR is not taken into
>>  account in the e820 mapping.
>>
>>  This patch removes the explicit BARs and registers the second region through
>>  the normal PCI code.
>>
>>  I've only tested with a Linux guest and the open source VMware VGA driver.
>>     
>
> I have a very similar patch on my HD but I haven't included it because
> it causes my testing Ms Windows install to stop detecting the card.  I
> just tested your patch and the same thing happens, i.e. with the patch
> it works as a vga card but is detected as an Unknown adapter and only
> the 640x480x8 mode can be used.  I can't explain this.
>   

Can you describe how you setup your Windows install?  I'll try to 
reproduce it and dig into it.

Regards,

Anthony Liguori

> Currently the io port numbers can be set by the guest and the memory
> io regions are fixed.  Earlier both settings were hardcoded.  This is
> because in one version of the X driver (which was/is the only
> documentation available) these settings were metioned as *the* correct
> values for this card.  This may of course cause different types of
> breakage but so far worked ok, except when it was found that in
> various combinations qemu segfaulted due to different PCI cards
> registering the same port range as our default.  When this happened I
> tried to make these settings settable through PCI registers but found
> that this broke Ms Windows.  Luckily Ms Windows still worked if only
> port ranges were assigned dynamically and the segfault went away so I
> left it at this but it perhaps needs better looking at.
>