<div dir="ltr">I don't know if the "alloca" change is a good idea. Some people consider it <a href="http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice">bad practice</a>, and looks like it's not used anywhere in wayland/weston code - but someone else should make that call.<div> </div><div>Otherwise, though, looks good.</div></div><div class="gmail_extra"> <div class="gmail_quote">On Tue, May 5, 2015 at 2:22 PM, Derek Foreman <<a href="mailto:derekf@osg.samsung.com" target="_blank">derekf@osg.samsung.com</a>> wrote: <blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Recent versions of Mesa have stopped exposing XRGB visuals for gl on some Intel GPUs. While this may be changed in Mesa eventually, it's not impossible that some other hardware in the future won't provide XRGB visuals either. Let's try again with an ARGB visual if XRGB is unavailable. Since we're not changing the scanout buffer format, and our current rendering loop always results in saturated alpha in the frame buffer, it should be Just Fine(tm) - and probably better than just exiting. Signed-off-by: Derek Foreman <<a href="mailto:derekf@osg.samsung.com">derekf@osg.samsung.com</a>> --- Dima Ryazanov called me out for fallback_format() not working on all endians, and I've reworked the loop to be a single loop instead of two, similar to Daniel's suggestion (but still keeping the NULL visual_id means "give me the first match" semantic of the original) I've also replaced calloc with aloca so I don't have to worry about freeing the array on return, which simplifies things a little bit. I didn't bother zeroing out the array, since it's filled in by eglChooseConfig. It's still an ugly function. :) src/gl-renderer.c | 57 +++++++++++++++++++++++++++++++++++++++++-------------- 1 file changed, 43 insertions(+), 14 deletions(-) diff --git a/src/gl-renderer.c b/src/gl-renderer.c index ae3122f..a4fd3a0 100644 --- a/src/gl-renderer.c +++ b/src/gl-renderer.c @@ -934,6 +934,14 @@ output_rotate_damage(struct weston_output *output, go->border_damage[go->buffer_damage_index] = border_status; } +/* NOTE: We now allow falling back to ARGB gl visual ids when XRGB is + * unavailable, so we're assuming the background has no transparency + * and that everything with a blend, like drop shadows, will have something + * opaque (like the background) drawn underneath it. + * + * Depending on the underlying hardware, violating that assumption could + * result in seeing through to another display plane. + */ static void gl_renderer_repaint_output(struct weston_output *output, pixman_region32_t *output_damage) @@ -1897,6 +1905,15 @@ log_egl_config_info(EGLDisplay egldpy, EGLConfig eglconfig) weston_log_continue(" unknown\n"); } +static EGLint +fallback_format(EGLint format) +{ + if ((format & 0xFF) != 'X') + return 0; + + return (format & 0xFFFFFF00) | 'A'; +} + static int egl_choose_config(struct gl_renderer *gr, const EGLint *attribs, const EGLint *visual_id, @@ -1904,41 +1921,53 @@ egl_choose_config(struct gl_renderer *gr, const EGLint *attribs, { EGLint count = 0; EGLint matched = 0; + EGLint fallback_id; EGLConfig *configs; + EGLConfig fallback_config = 0; int i; if (!eglGetConfigs(gr->egl_display, NULL, 0, &count) || count < 1) return -1; - configs = calloc(count, sizeof *configs); + configs = alloca(count * sizeof *configs); if (!configs) return -1; if (!eglChooseConfig(gr->egl_display, attribs, configs, count, &matched)) - goto out; + return -1; + + if (!matched) + return -1; + if (!visual_id) { + *config_out = configs[0]; + return 0; + } + + fallback_id = fallback_format(*visual_id); for (i = 0; i < matched; ++i) { EGLint id; - if (visual_id) { - if (!eglGetConfigAttrib(gr->egl_display, - configs[i], EGL_NATIVE_VISUAL_ID, - &id)) - continue; + if (!eglGetConfigAttrib(gr->egl_display, + configs[i], EGL_NATIVE_VISUAL_ID, + &id)) + continue; - if (id != 0 && id != *visual_id) - continue; + if (id == *visual_id) { + *config_out = configs[i]; + return 0; } + if (id == fallback_id) + fallback_config = configs[i]; + } - *config_out = configs[i]; - - free(configs); + if (fallback_config) { + weston_log("Falling back to ARGB visual\n"); + *config_out = fallback_config; return 0; } -out: - free(configs); return -1; } -- 2.1.4 </blockquote></div> </div>