[Mesa-dev] [PATCH v5 2/4] glx: implement __DRIbackgroundCallableExtension.isThreadSafe

[Gregory Hainaut]

v2:
bump version

v3:
Add code comment
s/IsGlThread/IsThread/ (and variation)

v4:
DRI3 doesn't hit X through GL call so it is always safe

Signed-off-by: Gregory Hainaut <gregory.hainaut at gmail.com>
---
 src/glx/dri2_glx.c | 15 ++++++++++++++-
 src/glx/dri3_glx.c | 12 +++++++++++-
 2 files changed, 25 insertions(+), 2 deletions(-)

diff --git a/src/glx/dri2_glx.c b/src/glx/dri2_glx.c
index 145f44d6e8..4f163688f2 100644
--- a/src/glx/dri2_glx.c
+++ b/src/glx/dri2_glx.c
@@ -946,20 +946,32 @@ dri2GetSwapInterval(__GLXDRIdrawable *pdraw)
   return priv->swap_interval;
 }
 
 static void
 driSetBackgroundContext(void *loaderPrivate)
 {
    struct dri2_context *pcp = (struct dri2_context *) loaderPrivate;
    __glXSetCurrentContext(&pcp->base);
 }
 
+static GLboolean
+driIsThreadSafe(void *loaderPrivate)
+{
+   struct dri2_context *pcp = (struct dri2_context *) loaderPrivate;
+   /* Check Xlib is running in thread safe mode
+    *
+    * 'lock_fns' is the XLockDisplay function pointer of the X11 display 'dpy'.
+    * It wll be NULL if XInitThreads wasn't called.
+    */
+   return pcp->base.psc->dpy->lock_fns != NULL;
+}
+
 static const __DRIdri2LoaderExtension dri2LoaderExtension = {
    .base = { __DRI_DRI2_LOADER, 3 },
 
    .getBuffers              = dri2GetBuffers,
    .flushFrontBuffer        = dri2FlushFrontBuffer,
    .getBuffersWithFormat    = dri2GetBuffersWithFormat,
 };
 
 static const __DRIdri2LoaderExtension dri2LoaderExtension_old = {
    .base = { __DRI_DRI2_LOADER, 3 },
@@ -967,23 +979,24 @@ static const __DRIdri2LoaderExtension dri2LoaderExtension_old = {
    .getBuffers              = dri2GetBuffers,
    .flushFrontBuffer        = dri2FlushFrontBuffer,
    .getBuffersWithFormat    = NULL,
 };
 
 static const __DRIuseInvalidateExtension dri2UseInvalidate = {
    .base = { __DRI_USE_INVALIDATE, 1 }
 };
 
 static const __DRIbackgroundCallableExtension driBackgroundCallable = {
-   .base = { __DRI_BACKGROUND_CALLABLE, 1 },
+   .base = { __DRI_BACKGROUND_CALLABLE, 2 },
 
    .setBackgroundContext    = driSetBackgroundContext,
+   .isThreadSafe            = driIsThreadSafe,
 };
 
 _X_HIDDEN void
 dri2InvalidateBuffers(Display *dpy, XID drawable)
 {
    __GLXDRIdrawable *pdraw =
       dri2GetGlxDrawableFromXDrawableId(dpy, drawable);
    struct dri2_screen *psc;
    struct dri2_drawable *pdp = (struct dri2_drawable *) pdraw;
 
diff --git a/src/glx/dri3_glx.c b/src/glx/dri3_glx.c
index e1dc5aa4a8..d07968e3c5 100644
--- a/src/glx/dri3_glx.c
+++ b/src/glx/dri3_glx.c
@@ -496,37 +496,47 @@ dri3_flush_front_buffer(__DRIdrawable *driDrawable, void *loaderPrivate)
    loader_dri3_wait_gl(draw);
 }
 
 static void
 dri_set_background_context(void *loaderPrivate)
 {
    struct dri3_context *pcp = (struct dri3_context *)loaderPrivate;
    __glXSetCurrentContext(&pcp->base);
 }
 
+static GLboolean
+dri_is_thread_safe(void *loaderPrivate)
+{
+   /* Unlike DRI2, DRI3 doesn't call GetBuffers/GetBuffersWithFormat
+    * during draw so we're safe here.
+    */
+   return true;
+}
+
 /* The image loader extension record for DRI3
  */
 static const __DRIimageLoaderExtension imageLoaderExtension = {
    .base = { __DRI_IMAGE_LOADER, 1 },
 
    .getBuffers          = loader_dri3_get_buffers,
    .flushFrontBuffer    = dri3_flush_front_buffer,
 };
 
 const __DRIuseInvalidateExtension dri3UseInvalidate = {
    .base = { __DRI_USE_INVALIDATE, 1 }
 };
 
 static const __DRIbackgroundCallableExtension driBackgroundCallable = {
-   .base = { __DRI_BACKGROUND_CALLABLE, 1 },
+   .base = { __DRI_BACKGROUND_CALLABLE, 2 },
 
    .setBackgroundContext = dri_set_background_context,
+   .isThreadSafe         = dri_is_thread_safe,
 };
 
 static const __DRIextension *loader_extensions[] = {
    &imageLoaderExtension.base,
    &dri3UseInvalidate.base,
    &driBackgroundCallable.base,
    NULL
 };
 
 /** dri3_swap_buffers
-- 
2.11.0