Kristian Høgsberg wrote:
> On Mon, Mar 30, 2009 at 4:46 AM, Thomas Hellstrom <[email protected]>
> wrote:
>
>> Hi!
>>
>> Thomas Hellstrom wrote:
>>
>>> Hi!
>>>
>>> I've sent two glx dri patches for review. The first one does some minor
>>> optimizations and propagates driver makeCurrent back.
>>> The second one is intended to fix the makeContextCurrent(NULL, None,
>>> None) call and to do some additional error checking. This was prompted
>>> by the newly added sharedtex_mt demo.
>>>
>>> Most if not all mesa dri drivers are still broken w r t to the above
>>> call, as it still does not get through to the driver makeCurrent hook.
>>> Instead the correct functionality needs to be implemented in the driver
>>> unbindContext hook, similar to the following:
>>>
>>> GLboolean
>>> viaUnbindContext(__DRIcontextPrivate * driContextPriv)
>>> {
>>> if (driContextPriv) {
>>> struct via_context *vmesa =
>>> (struct via_context *)driContextPriv->driverPrivate;
>>> GLcontext *ctx = vmesa->glCtx;
>>>
>>> GET_CURRENT_CONTEXT(oldctx);
>>> if (ctx == oldctx)
>>> VIA_FLUSH_DMA(vmesa);
>>>
>>> _mesa_make_current(NULL, NULL, NULL);
>>> }
>>>
>>> return GL_TRUE;
>>> }
>>>
>>>
>>>
>> Actually, the above code doesn't work, as unbindContext is always called
>> even if the new context and the old context are the same. Instead,
>> contexts need to be refcounted in the driver.
>>
>> /Thomas
>>
>>
>>
>>> In addition, if the context is changed in the driver makeCurrent hook,
>>> the driver needs to flush the old context first. That could
>>> theoretically also be done unbindContext, but since unbindContext is
>>> called on the old context _after_ makeCurrent, that may not be a good idea.
>>>
>
> Do you have a new patch on the way or do you want me to look at the
> ones you sent earlier?
>
> cheers,
> Kristian
>
Hi, Kristian!
The patches should be OK. It's the above sample code that should go in
each dri driver that doesn't work.
I have a code snippet instead that looks like this:
GLboolean
viaUnbindContext(__DRIcontextPrivate * driContextPriv)
{
if (driContextPriv) {
struct via_context *vmesa =
(struct via_context *)driContextPriv->driverPrivate;
GLcontext *ctx = vmesa->glCtx;
if (--vmesa->bindCount == 0) {
GET_CURRENT_CONTEXT(curctx);
if (ctx == curctx) {
VIA_FLUSH_DMA(vmesa);
_mesa_make_current(NULL, NULL, NULL);
}
}
}
return GL_TRUE;
}
and
GLboolean
viaMakeCurrent(__DRIcontextPrivate * driContextPriv,
__DRIdrawablePrivate * driDrawPriv,
__DRIdrawablePrivate * driReadPriv)
{
...
if (driContextPriv) {
struct via_context *vmesa =
(struct via_context *)driContextPriv->driverPrivate;
GLcontext *ctx = vmesa->glCtx;
GET_CURRENT_CONTEXT(oldctx);
if (ctx != oldctx && oldctx != NULL) {
VIA_FLUSH_DMA(VIA_CONTEXT(oldctx));
}
++vmesa->bindCount;
...
This combination should makeCurrent work as specified, namely
1) Always flush the old context before binding the new one.
2) Always flush the old context on makeCurrent(NULL, None, None);
While never attempting to flush a context that is not current.
Similar code needs to be added to each DRI driver, but that isn't a
requirement for pulling in the patches.
Thanks,
/Thomas
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