[Intel-gfx] [PATCH xf96-video-intel] DRI2GetMSC: Do not send a bogus ust when no drawable is not displayed

[Stéphane Marchesin]

On Fri, Mar 29, 2013 at 5:54 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> On Fri, Mar 29, 2013 at 03:13:35AM -0700, Stéphane Marchesin wrote:
>> On Fri, Mar 29, 2013 at 2:07 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
>> > On Fri, Mar 29, 2013 at 01:54:37PM +0800, Daniel Kurtz wrote:
>> >> According to the opengl glx_sync_control spec, the Unadjusted System Time
>> >> (or UST) is a 64-bit monotonically increasing counter that is available
>> >> throughout the system:
>> >> http://www.opengl.org/registry/specs/OML/glx_sync_control.txt
>> >>
>> >> Therefore, sending 0, even in this corner case, is out of spec.
>> >> Instead, just return FALSE indicating that the operation could not be
>> >> completed.
>> >
>> > The problem is that ends up sending BadDrawable back to the client,
>> > which ends up killing many clients and a compositor or two due to the
>> > unexpected error.
>> >
>> > Would you prefer querying pipe 0 in this case for the UST?
>>
>> For us it comes down to the fact that we'd like something monotonous.
>> So yes querying pipe 0 could work if it's enabled. But I wonder what
>> do you do when you have no enabled pipe though? Return the last UST?
>
> That's a problem as we would need a running pipe, which is not
> guaranteed. I wonder if CLOCK_MONOTONIC would suffice?

Yeah that's what I had in mind. Would that work for you?

Stéphane