[Mesa-dev] [PATCH 3/4] i965: Only enable __DRI2_ROBUSTNESS if kernel support is available

[Ian Romanick]

From: Ian Romanick <ian.d.romanick at intel.com>

Rather than always advertising the extension but failing to create a
context with reset notifiction, just don't advertise it.  I don't know
why it didn't occur to me to do it this way in the first place.

Signed-off-by: Ian Romanick <ian.d.romanick at intel.com>
Suggested-by: Kristian Høgsberg <krh at bitplanet.net>
Cc: "10.0" <mesa-stable at lists.freedesktop.org>
Cc: Kristian Høgsberg <krh at bitplanet.net>
---
 src/mesa/drivers/dri/i965/brw_context.c  | 15 ---------------
 src/mesa/drivers/dri/i965/intel_screen.c | 24 +++++++++++++++++++++++-
 2 files changed, 23 insertions(+), 16 deletions(-)

diff --git a/src/mesa/drivers/dri/i965/brw_context.c b/src/mesa/drivers/dri/i965/brw_context.c
index d5c18bb..67ac01c 100644
--- a/src/mesa/drivers/dri/i965/brw_context.c
+++ b/src/mesa/drivers/dri/i965/brw_context.c
@@ -682,21 +682,6 @@ brwCreateContext(gl_api api,
       }
    }
 
-   /* Notification of GPU resets requires hardware contexts and a kernel new
-    * enough to support DRM_IOCTL_I915_GET_RESET_STATS.
-    */
-   if (notify_reset &&
-       (brw->hw_ctx == NULL
-        || drm_intel_get_reset_stats(brw->hw_ctx, &brw->reset_count, NULL,
-                                     NULL))) {
-      /* This is the wrong error code, but the correct error code (one that
-       * will cause EGL to generate EGL_BAD_MATCH) doesn't seem to exist.
-       */
-      *dri_ctx_error = __DRI_CTX_ERROR_UNKNOWN_ATTRIBUTE;
-      intelDestroyContext(driContextPriv);
-      return false;
-   }
-
    brw_init_surface_formats(brw);
 
    if (brw->is_g4x || brw->gen >= 5) {
diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
index 81901cc..051c000 100644
--- a/src/mesa/drivers/dri/i965/intel_screen.c
+++ b/src/mesa/drivers/dri/i965/intel_screen.c
@@ -899,6 +899,15 @@ static const __DRIextension *intelScreenExtensions[] = {
     &intelImageExtension.base,
     &intelRendererQueryExtension.base,
     &dri2ConfigQueryExtension.base,
+    NULL
+};
+
+static const __DRIextension *intelRobustScreenExtensions[] = {
+    &intelTexBufferExtension.base,
+    &intelFlushExtension.base,
+    &intelImageExtension.base,
+    &intelRendererQueryExtension.base,
+    &dri2ConfigQueryExtension.base,
     &dri2Robustness.base,
     NULL
 };
@@ -1323,7 +1332,20 @@ __DRIconfig **intelInitScreen2(__DRIscreen *psp)
 
    set_max_gl_versions(intelScreen);
 
-   psp->extensions = intelScreenExtensions;
+   /* Notification of GPU resets requires hardware contexts and a kernel new
+    * enough to support DRM_IOCTL_I915_GET_RESET_STATS.  If the ioctl is
+    * supported, calling it with a context of 0 will either generate EPERM or
+    * no error.  If the ioctl is not supported, it always generate EINVAL.
+    * Use this to determine whether to advertise the __DRI2_ROBUSTNESS
+    * extension to the loader.
+    */
+   struct drm_i915_reset_stats stats;
+   memset(&stats, 0, sizeof(stats));
+
+   const int ret = drmIoctl(psp->fd, DRM_IOCTL_I915_GET_RESET_STATS, &stats);
+
+   psp->extensions = (ret == -1 && errno == EINVAL)
+      ? intelScreenExtensions : intelRobustScreenExtensions;
 
    return (const __DRIconfig**) intel_screen_make_configs(psp);
 }
-- 
1.8.1.4