[PATCH] drm: introduce drm_can_sleep and use in intel/radeon drivers.

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

So we have a few places where the drm drivers would like to sleep to
be nice to the system, mainly in the modesetting paths, but we also
have two cases were atomic modesetting must take place, panic writing
and kernel debugger. So provide a central inline to determine if a
sleep or delay should be used and use this in the intel and radeon drivers.

Based on patch from Michel Dänzer <michel.daenzer at amd.com>

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=43941

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 drivers/gpu/drm/i915/intel_drv.h |    4 ++--
 drivers/gpu/drm/radeon/atom.c    |    2 ++
 include/drm/drmP.h               |    8 ++++++++
 3 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index a1b4343..cf2326b 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -39,7 +39,7 @@
 			ret__ = -ETIMEDOUT;				\
 			break;						\
 		}							\
-		if (W && !(in_atomic() || in_dbg_master())) msleep(W);	\
+		if (W && drm_can_sleep()) msleep(W);	\
 	}								\
 	ret__;								\
 })
@@ -48,7 +48,7 @@
 #define wait_for_atomic(COND, MS) _wait_for(COND, MS, 0)
 
 #define MSLEEP(x) do { \
-	if (in_dbg_master()) \
+	if (!drm_can_sleeep()) \
 		mdelay(x); \
 	else \
 		msleep(x); \
diff --git a/drivers/gpu/drm/radeon/atom.c b/drivers/gpu/drm/radeon/atom.c
index 14cc88a..d1bd239 100644
--- a/drivers/gpu/drm/radeon/atom.c
+++ b/drivers/gpu/drm/radeon/atom.c
@@ -665,6 +665,8 @@ static void atom_op_delay(atom_exec_context *ctx, int *ptr, int arg)
 	SDEBUG("   count: %d\n", count);
 	if (arg == ATOM_UNIT_MICROSEC)
 		udelay(count);
+	else if (!drm_can_sleep())
+		mdelay(count);
 	else
 		msleep(count);
 }
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 1f9e951..f1c01bc 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1696,5 +1696,13 @@ extern void drm_platform_exit(struct drm_driver *driver, struct platform_device
 extern int drm_get_platform_dev(struct platform_device *pdev,
 				struct drm_driver *driver);
 
+/* returns true if currently okay to sleep */
+static __inline__ bool drm_can_sleep(void)
+{
+	if (in_atomic() || in_dbg_master() || irqs_disabled())
+		return false;
+	return true;
+}
+
 #endif				/* __KERNEL__ */
 #endif
-- 
1.7.7.3