[PATCH] hw/display/bcm2835_fb: fix fb_use_offsets condition

[SamJakob]

        It is common practice when implementing double-buffering
        on VideoCore to do so by multiplying the height of the
        virtual buffer by the number of virtual screens desired
        (i.e., two - in the case of double-bufferring).

        At present, this won't work in QEMU because the logic in
        fb_use_offsets require that both the virtual width and
        height exceed their physical counterparts.

        This appears to be unintentional/a typo and indeed the
        comment states; "Experimentally, the hardware seems to
        do this only if the viewport size is larger than the
        physical screen". The viewport/virtual size would be
        larger than the physical size if either virtual dimension
        were larger than their physical counterparts and not
        necessarily both.

Signed-off-by: SamJakob <me@samjakob.com>
---
 hw/display/bcm2835_fb.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/display/bcm2835_fb.c b/hw/display/bcm2835_fb.c
index e40ed2d2e1..650db3da82 100644
--- a/hw/display/bcm2835_fb.c
+++ b/hw/display/bcm2835_fb.c
@@ -145,7 +145,7 @@ static bool fb_use_offsets(BCM2835FBConfig *config)
      * viewport size is larger than the physical screen. (It doesn't
      * prevent the guest setting this silly viewport setting, though...)
      */
-    return config->xres_virtual > config->xres &&
+    return config->xres_virtual > config->xres ||
         config->yres_virtual > config->yres;
 }
 
-- 
2.45.2