[Intel-gfx] [RFC 1/6] drm/i915: cover ioctls with runtime_get/put

[naresh.kumar.kachhi at intel.com]

From: Naresh Kumar Kachhi <naresh.kumar.kachhi at intel.com>

With runtime PM enabled, we need to make sure that all HW access
are valid (i.e.  Gfx is in D0). Invalid accesses might end up in
HW hangs. Ex. A hang is seen if display register is accessed on
BYT while display power island is power gated.

This patch is covering all the IOCTLs with get/put.
TODO: limit runtime_get/put to IOCTLs that accesses HW

Signed-off-by: Naresh Kumar Kachhi <naresh.kumar.kachhi at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c   | 21 ++++++++++++++++++++-
 drivers/gpu/drm/i915/i915_ioc32.c | 11 +++++++++--
 2 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 82c4605..80965be 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -845,6 +845,25 @@ i915_pci_remove(struct pci_dev *pdev)
 	drm_put_dev(dev);
 }
 
+static long i915_unlocked_ioctl(struct file *filp,
+	      unsigned int cmd, unsigned long arg)
+{
+	struct drm_file *file_priv = filp->private_data;
+	struct drm_device *dev = file_priv->minor->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	int ret;
+
+	/* Don't do anything if device is not ready */
+	if (drm_device_is_unplugged(dev))
+		return -ENODEV;
+
+	intel_runtime_pm_get(dev_priv);
+	ret = drm_ioctl(filp, cmd, arg);
+	intel_runtime_pm_put(dev_priv);
+
+	return ret;
+}
+
 static int i915_pm_suspend(struct device *dev)
 {
 	struct pci_dev *pdev = to_pci_dev(dev);
@@ -970,7 +989,7 @@ static const struct file_operations i915_driver_fops = {
 	.owner = THIS_MODULE,
 	.open = drm_open,
 	.release = drm_release,
-	.unlocked_ioctl = drm_ioctl,
+	.unlocked_ioctl = i915_unlocked_ioctl,
 	.mmap = drm_gem_mmap,
 	.poll = drm_poll,
 	.read = drm_read,
diff --git a/drivers/gpu/drm/i915/i915_ioc32.c b/drivers/gpu/drm/i915/i915_ioc32.c
index 3c59584..bfc773e 100644
--- a/drivers/gpu/drm/i915/i915_ioc32.c
+++ b/drivers/gpu/drm/i915/i915_ioc32.c
@@ -201,12 +201,17 @@ static drm_ioctl_compat_t *i915_compat_ioctls[] = {
  */
 long i915_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 {
+	struct drm_file *file_priv = filp->private_data;
+	struct drm_device *dev = file_priv->minor->dev;
 	unsigned int nr = DRM_IOCTL_NR(cmd);
 	drm_ioctl_compat_t *fn = NULL;
 	int ret;
 
-	if (nr < DRM_COMMAND_BASE)
-		return drm_compat_ioctl(filp, cmd, arg);
+	intel_runtime_pm_get(dev->dev_private);
+	if (nr < DRM_COMMAND_BASE) {
+		ret = drm_compat_ioctl(filp, cmd, arg);
+		goto out;
+	}
 
 	if (nr < DRM_COMMAND_BASE + DRM_ARRAY_SIZE(i915_compat_ioctls))
 		fn = i915_compat_ioctls[nr - DRM_COMMAND_BASE];
@@ -216,6 +221,8 @@ long i915_compat_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 	else
 		ret = drm_ioctl(filp, cmd, arg);
 
+out:
+	intel_runtime_pm_put(dev->dev_private);
 	return ret;
 }
 #endif
-- 
1.8.1.2