Re: [Xen-devel] [PATCH] xen/video: Set EFI framebuffer to WC by default

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 11.06.15 at 15:03, <ross.lagerwall@xxxxxxxxxx> wrote:
> On 06/11/2015 01:35 PM, Jan Beulich wrote:
>>>>> On 11.06.15 at 14:09, <ross.lagerwall@xxxxxxxxxx> wrote:
>>> Both Linux and FreeBSD map the EFI framebuffer as write-combining by
>>> default, so I assume (hope) that this is a safe change to make.
>>
>> No, an unaware Dom0 OS may not work correctly when the frame
>> buffer is WC. It also might come as a surprise to the Dom0 OS that
>> there is a WC range in one of the MTRRs where none would be
>> expected. Plus - why for EFI only?
> 
> Because that's what other OSes did, but if it's not going to work... I 
> can send a patch which we're currently using which sticks in a few 
> process_pending_softirqs() in strategic places.

Yes please (quite a few of them seem to be debug level ones only
anyway, i.e. not usually a problem on production systems).

Jan


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