On 05/08/2013 11:50 PM, Jonas Ådahl wrote:
On Tue, Apr 23, 2013 at 3:54 PM, Ander Conselvan de Oliveira
<ander.conselvan.de.olive...@intel.com> wrote:
Linux kernel 3.8 shipped with a bug in the prime fd passing code that
makes it unreliable. As of this writing, it seems unlikely that 3.9
will contain the fix for the issue.
This patch disable prime support when running on top of those kernels,
in order to prevent unexpected behavior when running a Wayland
compositor.
Commit be8a42ae60addd8b6092535c11b42d099d6470ec in Linus tree introduces
the problem, which can be fixed by the patch below (not upstream yet):
http://lists.freedesktop.org/archives/dri-devel/2013-April/037716.html
---
src/egl/drivers/dri2/egl_dri2.c | 36 +++++++++++++++++++++++++++++++++++-
1 file changed, 35 insertions(+), 1 deletion(-)
diff --git a/src/egl/drivers/dri2/egl_dri2.c b/src/egl/drivers/dri2/egl_dri2.c
index 06a21d7..13b9107 100644
--- a/src/egl/drivers/dri2/egl_dri2.c
+++ b/src/egl/drivers/dri2/egl_dri2.c
@@ -38,6 +38,7 @@
#include <GL/internal/dri_interface.h>
#include <sys/types.h>
#include <sys/stat.h>
+#include <sys/utsname.h>
#include "egl_dri2.h"
@@ -1557,6 +1558,38 @@ static struct wayland_drm_callbacks wl_drm_callbacks = {
};
static EGLBoolean
+kernel_prime_support_not_buggy()
+{
+ struct utsname un;
+
+ /* Linux kernel 3.8 shipped with a bug in the prime fd passing code that
+ * makes it unreliable. As of this writing, it seems unlikely that 3.9
+ * will contain the fix for the issue. Disable prime support when running
+ * on top of those kernels, in order to prevent unexpected behavior when
+ * running a Wayland compositor.
+ *
+ * Commit be8a42ae60addd8b6092535c11b42d099d6470ec in Linus tree introduces
+ * the problem, which can be fixed by the patch below (not upstream yet):
+ * http://lists.freedesktop.org/archives/dri-devel/2013-April/037716.html
+ */
+ if (uname(&un) == -1) {
+ _eglLog(_EGL_INFO,
+ "DRI2: wayland prime support disabled: unknown kernel version");
+ return EGL_FALSE;
+ }
+
+ if (strncmp(un.sysname, "Linux", strlen("Linux")) == 0 &&
+ (strncmp(un.release, "3.8.", strlen("3.8.")) == 0 ||
+ strncmp(un.release, "3.9.", strlen("3.9.")) == 0)) {
I think if we should test against kernel releases we can disable for
anything older than the first release that has the fix as it doesn't
seem to work on older versions either. At least in my case I get what
looks like the same issue when prime support enabled when running
kernel version 3.5.
Your distro probably picked up the patch that introduces the bug. But
anyway, I think this patch should just be dropped. It doesn't really
solve the issue.
There's no Mesa release with prime support yet, so I guess we should
just disable it for now, until things are solved on the kernel side.
Cheers,
Ander
Jonas
+ _eglLog(_EGL_INFO,
+ "DRI2: wayland prime support disabled: buggy kernel");
+ return EGL_FALSE;
+ }
+
+ return EGL_TRUE;
+}
+
+static EGLBoolean
dri2_bind_wayland_display_wl(_EGLDriver *drv, _EGLDisplay *disp,
struct wl_display *wl_dpy)
{
@@ -1575,7 +1608,8 @@ dri2_bind_wayland_display_wl(_EGLDriver *drv, _EGLDisplay
*disp,
ret = drmGetCap(dri2_dpy->fd, DRM_CAP_PRIME, &cap);
if (ret == 0 && cap == (DRM_PRIME_CAP_IMPORT | DRM_PRIME_CAP_EXPORT) &&
dri2_dpy->image->base.version >= 7 &&
- dri2_dpy->image->createImageFromFds != NULL)
+ dri2_dpy->image->createImageFromFds != NULL &&
+ kernel_prime_support_not_buggy())
flags |= WAYLAND_DRM_PRIME;
dri2_dpy->wl_server_drm =
--
1.7.10.4
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