From a203eaa4f4fb672b95426289b8dad3a8998f92d7 Mon Sep 17 00:00:00 2001 From: Bart Oldeman Date: Sun, 3 Feb 2019 02:57:10 +0000 Subject: [PATCH] gallium-xlib: query MIT-SHM before using it. When Mesa is compiled for gallium-xlib using e.g. ./configure --enable-glx=gallium-xlib --disable-dri --disable-gbm -disable-egl and is used by an X server (usually remotely via SSH X11 forwarding) that does not support MIT-SHM such as XMing or MobaXterm, OpenGL clients report error messages such as Xlib: extension "MIT-SHM" missing on display "localhost:11.0". ad infinitum. The reason is that the code in src/gallium/winsys/sw/xlib uses MIT-SHM without checking for its existence, unlike the code in src/glx/drisw_glx.c and src/mesa/drivers/x11/xm_api.c. I copied the same check using XQueryExtension, and tested with glxgears on MobaXterm. This issue was reported before here: https://lists.freedesktop.org/archives/mesa-users/2016-July/001183.html Reviewed-by: Eric Anholt Reviewed-by: Emil Velikov Cc: --- src/gallium/winsys/sw/xlib/xlib_sw_winsys.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/src/gallium/winsys/sw/xlib/xlib_sw_winsys.c b/src/gallium/winsys/sw/xlib/xlib_sw_winsys.c index 8753139107c..a4c1d50453b 100644 --- a/src/gallium/winsys/sw/xlib/xlib_sw_winsys.c +++ b/src/gallium/winsys/sw/xlib/xlib_sw_winsys.c @@ -396,6 +396,7 @@ xlib_displaytarget_create(struct sw_winsys *winsys, { struct xlib_displaytarget *xlib_dt; unsigned nblocksy, size; + int ignore; xlib_dt = CALLOC_STRUCT(xlib_displaytarget); if (!xlib_dt) @@ -410,7 +411,8 @@ xlib_displaytarget_create(struct sw_winsys *winsys, xlib_dt->stride = align(util_format_get_stride(format, width), alignment); size = xlib_dt->stride * nblocksy; - if (!debug_get_option_xlib_no_shm()) { + if (!debug_get_option_xlib_no_shm() && + XQueryExtension(xlib_dt->display, "MIT-SHM", &ignore, &ignore, &ignore)) { xlib_dt->data = alloc_shm(xlib_dt, size); if (xlib_dt->data) { xlib_dt->shm = True; -- 2.30.2