drm/omap: add pin refcounting to omap_framebuffer
omap_framebuffer_pin() and omap_framebuffer_unpin() are currently
broken, as they cannot be called multiple times (i.e. pin, pin, unpin,
unpin), which is what happens in certain cases. This issue causes the
driver to possibly use 0 as an address for a displayed buffer, leading
to OCP error from DSS.
This patch fixes the issue by adding a simple pin_count, used to track
the number of pins.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/gpu/drm/omapdrm/omap_fb.c b/drivers/gpu/drm/omapdrm/omap_fb.c
index 45dd9ee..d1e5f6d 100644
--- a/drivers/gpu/drm/omapdrm/omap_fb.c
+++ b/drivers/gpu/drm/omapdrm/omap_fb.c
@@ -86,6 +86,7 @@
struct omap_framebuffer {
struct drm_framebuffer base;
+ int pin_count;
const struct format *format;
struct plane planes[4];
};
@@ -249,6 +250,11 @@
struct omap_framebuffer *omap_fb = to_omap_framebuffer(fb);
int ret, i, n = drm_format_num_planes(fb->pixel_format);
+ if (omap_fb->pin_count > 0) {
+ omap_fb->pin_count++;
+ return 0;
+ }
+
for (i = 0; i < n; i++) {
struct plane *plane = &omap_fb->planes[i];
ret = omap_gem_get_paddr(plane->bo, &plane->paddr, true);
@@ -257,6 +263,8 @@
omap_gem_dma_sync(plane->bo, DMA_TO_DEVICE);
}
+ omap_fb->pin_count++;
+
return 0;
fail:
@@ -275,6 +283,11 @@
struct omap_framebuffer *omap_fb = to_omap_framebuffer(fb);
int ret, i, n = drm_format_num_planes(fb->pixel_format);
+ omap_fb->pin_count--;
+
+ if (omap_fb->pin_count > 0)
+ return 0;
+
for (i = 0; i < n; i++) {
struct plane *plane = &omap_fb->planes[i];
ret = omap_gem_put_paddr(plane->bo);