Commit 9e5a25f1 authored by Marc-André Lureau's avatar Marc-André Lureau Committed by Gerd Hoffmann
Browse files

qxl: keep going if reaching guest bug on empty area 

Xorg server hangs when using xfig and typing a text with space:
 #0  qxl_wait_for_io_command (qxl=<value optimized out>) at qxl_io.c:47
 #1  0x00007f826a49a299 in qxl_download_box (surface=0x221d030, x1=231, y1=259,
     x2=<value optimized out>, y2=<value optimized out>) at qxl_surface.c:143

       while (!(ram_header->int_pending & QXL_INTERRUPT_IO_CMD))
         usleep (1);

The QXL driver is calling QXL_IO_UPDATE_AREA with an empty area. This
is a guest bug. The call is async and no ack is sent back on guest
bug, so the X server will hang. The driver should be improved to avoid
this situation and also to abort on QXL_INTERRUPT_ERROR. This will be
a different patch series for the driver. However, it is simple enough
to keep qemu running on empty areas update, which is what this patch
provides.

https://bugzilla.redhat.com/show_bug.cgi?id=1151363



Signed-off-by: default avatarGerd Hoffmann <kraxel@redhat.com>
parent b1d28ec6

hw/display/qxl.c

+5 −0
Original line number Diff line number Diff line
@@ -1591,6 +1591,11 @@ async_common: 
            qxl_set_guest_bug(d,

                    "QXL_IO_UPDATE_AREA: invalid area (%ux%u)x(%ux%u)\n",

                    update.left, update.top, update.right, update.bottom);

            if (update.left == update.right || update.top == update.bottom) {

                /* old drivers may provide empty area, keep going */

                qxl_clear_guest_bug(d);

                goto cancel_async;

            }

            break;

        }

        if (async == QXL_ASYNC) {