During system resume we depended on pci_enable_device() also putting the device into PCI D0 state. This won't work if the PCI device was already enabled but still in D3 state. This is because pci_enable_device() is refcounted and will not change the HW state if called with a non-zero refcount. Leaving the device in D3 will make all subsequent device accesses fail. This didn't cause a problem most of the time, since we resumed with an enable refcount of 0. But it fails at least after module reload because after that we also happen to leak a PCI device enable reference: During probing we call drm_get_pci_dev() which will enable the PCI device, but during device removal drm_put_dev() won't disable it. This is a bug of its own in DRM core, but without much harm as it only leaves the PCI device enabled. Fixing it is also a bit more involved, due to DRM mid-layering and because it affects non-i915 drivers too. The fix in this patch is valid regardless of the problem in DRM core. CC: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> CC: stable@xxxxxxxxxxxxxxx Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_drv.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index d550ae2..7eaa93e 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -803,7 +803,7 @@ static int i915_drm_resume(struct drm_device *dev) static int i915_drm_resume_early(struct drm_device *dev) { struct drm_i915_private *dev_priv = dev->dev_private; - int ret = 0; + int ret; /* * We have a resume ordering issue with the snd-hda driver also @@ -814,6 +814,13 @@ static int i915_drm_resume_early(struct drm_device *dev) * FIXME: This should be solved with a special hdmi sink device or * similar so that power domains can be employed. */ + + ret = pci_set_power_state(dev->pdev, PCI_D0); + if (ret) { + DRM_ERROR("failed to set PCI D0 power state (%d)\n", ret); + goto out; + } + if (pci_enable_device(dev->pdev)) { ret = -EIO; goto out; -- 2.5.0 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html