On 05/11/2011 04:50 PM, Jan Kiszka wrote:
On 2011-05-11 15:26, Avi Kivity wrote:
> On 05/11/2011 04:08 PM, Jan Kiszka wrote:
>> On 2011-05-11 13:25, Avi Kivity wrote:
>>> On 05/09/2011 06:48 PM, Alex Williamson wrote:
>>>>> That's an interesting trace! We'll check this here, but I bet it
>>>>> contributes to the problems. Our FX 3800 has 1G memory...
>>>>
>>>> Yes, qemu leaves far too little MMIO space to think about assigning
>>>> graphics cards. Both of my cards have 512MB and I hacked qemu to leave
>>>> a bigger gap via something like:
>>>>
>>>
>>> What about 64-bit BARs?
>>
>> Aren't they backward compatible? Or do you think some guest drivers may
>> assume to find their 64-bit capable bars also registered as such and get
>> upset when seeing them as 32-bit ones?
>>
>
> I mean, if you have a 1GB framebuffer, put it above 4GB and hope the
> OS/driver can handle it.
The question is if the drivers actually depend on this. At least the
binary nvidia thing here on my notebook, it is obviously happy with
below-4G-bars (and likely change the mapped window on demand):
01:00.0 VGA compatible controller: nVidia Corporation GT216 [Quadro FX 880M] (rev a2) (prog-if 00 [VGA controller])
Subsystem: Fujitsu Limited. Device 1584
Flags: bus master, fast devsel, latency 0, IRQ 16
Memory at cc000000 (32-bit, non-prefetchable) [size=16M]
Memory at d0000000 (64-bit, prefetchable) [size=256M]
Memory at ce000000 (64-bit, prefetchable) [size=32M]
I/O ports at 2000 [size=128]
[virtual] Expansion ROM at cd000000 [disabled] [size=512K]
Capabilities: [60] Power Management version 3
Capabilities: [68] MSI: Enable- Count=1/1 Maskable- 64bit+
Capabilities: [78] Express Endpoint, MSI 00
Capabilities: [b4] Vendor Specific Information: Len=14<?>
Capabilities: [100] Virtual Channel
Capabilities: [128] Power Budgeting<?>
Capabilities: [600] Vendor Specific Information: ID=0001 Rev=1 Len=024<?>
Kernel driver in use: nvidia
Maybe the crashing Windows driver of the FX3800 has different
requirements.
I doubt it. A 64-bit BAR would be configured as 32-bit on an older
BIOS, no?
I'd guess 64-bit BARs are only needed for large BARs.
--
error compiling committee.c: too many arguments to function
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