drm: add option to force writeback off.
In order to get some better debugging from people about certain hangs/crashes
we need to be able to turn AGP writeback off permanently...
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/char/drm/radeon_cp.c b/drivers/char/drm/radeon_cp.c
index 447bfbe..e64d680 100644
--- a/drivers/char/drm/radeon_cp.c
+++ b/drivers/char/drm/radeon_cp.c
@@ -1205,6 +1205,10 @@
dev_priv->writeback_works = 0;
DRM_DEBUG("writeback test failed\n");
}
+ if (radeon_no_wb == 1) {
+ dev_priv->writeback_works = 0;
+ DRM_DEBUG("writeback forced off\n");
+ }
dev_priv->sarea_priv->last_frame = dev_priv->scratch[0] = 0;
RADEON_WRITE(RADEON_LAST_FRAME_REG, dev_priv->sarea_priv->last_frame);
diff --git a/drivers/char/drm/radeon_drv.c b/drivers/char/drm/radeon_drv.c
index 6c17661..7074d01 100644
--- a/drivers/char/drm/radeon_drv.c
+++ b/drivers/char/drm/radeon_drv.c
@@ -37,6 +37,11 @@
#include "drm_pciids.h"
+int radeon_no_wb;
+
+MODULE_PARM_DESC(no_wb, "Disable AGP writeback for scratch registers\n");
+module_param_named(no_wb, radeon_no_wb, int, 0444);
+
static int postinit(struct drm_device *dev, unsigned long flags)
{
DRM_INFO("Initialized %s %d.%d.%d %s on minor %d: %s\n",
diff --git a/drivers/char/drm/radeon_drv.h b/drivers/char/drm/radeon_drv.h
index e360769..3c74734 100644
--- a/drivers/char/drm/radeon_drv.h
+++ b/drivers/char/drm/radeon_drv.h
@@ -281,6 +281,7 @@
u32 age;
} drm_radeon_buf_priv_t;
+extern int radeon_no_wb;
/* radeon_cp.c */
extern int radeon_cp_init(DRM_IOCTL_ARGS);
extern int radeon_cp_start(DRM_IOCTL_ARGS);