drm/i915: Disable mmio debugging during user access
If the user bypasses i915 and accesses mmio directly, that easily
confuses our automatic mmio debugging (any error we then detect is
likely to be as a result of the user). Since we expect userspace to open
debugfs/i915_forcewake_user if i915.ko is loaded and they want mmio
access, that makes the opportune time to disable our debugging for
duration of the bypass.
v2: Move the fiddling of uncore internals to uncore.c
References: https://bugs.freedesktop.org/show_bug.cgi?id=102543
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Reviewed-by: Mika Kuoppala <mika.kuoppala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170907134441.12881-1-chris@chris-wilson.co.uk
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index 8d432e5..6338018 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -1421,6 +1421,9 @@ static int i915_forcewake_domains(struct seq_file *m, void *data)
struct intel_uncore_forcewake_domain *fw_domain;
unsigned int tmp;
+ seq_printf(m, "user.bypass_count = %u\n",
+ i915->uncore.user_forcewake.count);
+
for_each_fw_domain(fw_domain, i915, tmp)
seq_printf(m, "%s.wake_count = %u\n",
intel_uncore_forcewake_domain_to_str(fw_domain->id),
@@ -4724,26 +4727,26 @@ static int i915_sseu_status(struct seq_file *m, void *unused)
static int i915_forcewake_open(struct inode *inode, struct file *file)
{
- struct drm_i915_private *dev_priv = inode->i_private;
+ struct drm_i915_private *i915 = inode->i_private;
- if (INTEL_GEN(dev_priv) < 6)
+ if (INTEL_GEN(i915) < 6)
return 0;
- intel_runtime_pm_get(dev_priv);
- intel_uncore_forcewake_get(dev_priv, FORCEWAKE_ALL);
+ intel_runtime_pm_get(i915);
+ intel_uncore_forcewake_user_get(i915);
return 0;
}
static int i915_forcewake_release(struct inode *inode, struct file *file)
{
- struct drm_i915_private *dev_priv = inode->i_private;
+ struct drm_i915_private *i915 = inode->i_private;
- if (INTEL_GEN(dev_priv) < 6)
+ if (INTEL_GEN(i915) < 6)
return 0;
- intel_uncore_forcewake_put(dev_priv, FORCEWAKE_ALL);
- intel_runtime_pm_put(dev_priv);
+ intel_uncore_forcewake_user_put(i915);
+ intel_runtime_pm_put(i915);
return 0;
}