Re: [PATCH 2/2] glamor: Address GLAMOR/UXA flushing problem.

[Chris Wilson <chris@chris-wilson.co.uk>]

On Tue, 15 Nov 2011 19:36:14 +0800, Zhigang Gong <zhigang.gong@linux.intel.com> wrote:
> This commit introduces a new function in UXA layer need_flush
> which is used to let the UXA layer to notify the lower layer
> that some pixmap get modified by GLAMOR. And then the intel
> driver could know it need to flush front buffer latter.
> 
> This commit also adds some necessary flushing pointis for UXA
> layer and glamor layer. Basicly, there are three scenarios:
> 
> 1. Before calling into glamor layer, it needs to flush all the
> corresponding UXA batch comand buffer.
> 
> 2. After calling the glamor rendering functions, it needs to
> flush the pending GL operations.
> 
> 3. Before we map a pixmap's BO, we also need to flush all the
> pending GL operations.
> 
> The scenario 2 could be eliminated when we fully change to glamor
> path.

I much prefer the one-sided uxa_prepare_access() you have implemented
here for the glamor side. For completeness, you still probably want the
uxa_finish_access() though. Alternatively you need to mark up all
operations with uxa_prepare_access(GLAMOR | NATIVE | SW, READ | WRITE)
which then perform the implicit uxa_finish_access() when the mode
changes, and would also allow you to only flush the glamor operations as
required.

Aside from that, this looks like the right approach to handling the
flushing.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre