Hi,
On 17-08-16 16:44, Keith Packard wrote:
Hans de Goede <[email protected]> writes:
Some code paths end up in msSharePixmapBacking with a pixmap
which does not have its usage_hint set to sharable.
This causes glamor_fd_from_pixmap() to create a non-linear bo,
which is wrong for a shared pixmap.
This commits sets the pixmap usage hint to shared before
calling glamor_fd_from_pixmap(), fixing this.
Specifically this fixes mis-rendering when running the mode
setting driver on the master gpu in a dual-gpu setup and
running an opengl app with DRI_PRIME=1.
One could argue that this is a problem of the caller, but the
usage_hint is as the name implies just a hint. I've tried
tracing the DRI_PRIME case from above, but the pixmap
ends up coming from a drawable passed into the server by
a client.
Signed-off-by: Hans de Goede <[email protected]>
---
hw/xfree86/drivers/modesetting/driver.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/hw/xfree86/drivers/modesetting/driver.c
b/hw/xfree86/drivers/modesetting/driver.c
index 5ebb394..023d491 100644
--- a/hw/xfree86/drivers/modesetting/driver.c
+++ b/hw/xfree86/drivers/modesetting/driver.c
@@ -1382,7 +1382,12 @@ msSharePixmapBacking(PixmapPtr ppix, ScreenPtr screen,
void **handle)
int ret;
CARD16 stride;
CARD32 size;
+ unsigned orig_usage_hint = ppix->usage_hint;
+
+ /* Ensure that glamor_fd_from_pixmap creates a sharable (linear) bo */
+ ppix->usage_hint = CREATE_PIXMAP_USAGE_SHARED;
ret = glamor_fd_from_pixmap(ppix->drawable.pScreen, ppix, &stride, &size);
+ ppix->usage_hint = orig_usage_hint;
That just can't be the right way to fix this...
That is what I thought, see the commit message. Trying to come up
with a better fix did not get me anywhere.
An alternative solution would be to add a flag argument to
glamor_fd_from_pixmap, so that callers like this one which
know for sure they want a linear bo can specify that through
a flag, and other callers can just pass in:
ppix->usage_hint == CREATE_PIXMAP_USAGE_SHARED
For that flag, the reason I did not do that is because
glamor_fd_from_pixmap is part of the xserver ABI AFAICT.
> Not that I have a better idea at this point.
Is that a convoluted way of acking the patch ? :)
Regards,
Hans
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