On Wed, May 25, 2016 at 04:55:35PM +0300, Mika Westerberg wrote:
On Wed, May 25, 2016 at 12:53:01AM +0200, Peter Wu wrote:
Since "PCI: Add runtime PM support for PCIe ports", the parent PCIe port can be runtime-suspended which disables power resources via ACPI. This is incompatible with DSM, resulting in a GPU device which is still in D3 and locks up the kernel on resume.
Mirror the behavior of Windows 8 and newer[1] (as observed via an AMLi debugger trace) and stop using the DSM functions for D3cold when power resources are available on the parent PCIe port.
Signed-off-by: Peter Wu peter@lekensteyn.nl
drivers/gpu/drm/nouveau/nouveau_acpi.c | 34 ++++++++++++++++++++++++++++++---- 1 file changed, 30 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c index df9f73e..e469df7 100644 --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c @@ -46,6 +46,7 @@ static struct nouveau_dsm_priv { bool dsm_detected; bool optimus_detected; bool optimus_flags_detected;
- bool optimus_skip_dsm; acpi_handle dhandle; acpi_handle rom_handle;
} nouveau_dsm_priv; @@ -212,8 +213,26 @@ static const struct vga_switcheroo_handler nouveau_dsm_handler = { .get_client_id = nouveau_dsm_get_client_id, };
+/* Firmware supporting Windows 8 or later do not use _DSM to put the device into
- D3cold, they instead rely on disabling power resources on the parent. */
+static bool nouveau_pr3_present(struct pci_dev *pdev) +{
- struct pci_dev *parent_pdev = pci_upstream_bridge(pdev);
- struct acpi_device *ad;
Nit: please call this adev instead of ad.
Will do.
- if (!parent_pdev)
return false;- ad = ACPI_COMPANION(&parent_pdev->dev);
- if (!ad)
return false;- return ad->power.flags.power_resources;
Is this sufficient to tell if the parent device has _PR3? I thought it returns true if it has power resources in general, not necessarily _PR3.
Otherwise this looks okay to me.
It is indeed set whenever there is any _PRx method. I wonder if it is appropriate to access fields directly like this, perhaps this would be more accurate (based on device_pm.c):
/* Check whether the _PR3 method is available. */ return adev->power.states[ACPI_STATE_D3_COLD].flags.valid;
I am also considering adding a check in case the pcieport driver does not support D3cold via runtime PM, what do you think of this?
if (!parent_pdev) return false; /* If the PCIe port does not support D3cold via runtime PM, allow a * fallback to the Optimus DSM method to put the device in D3cold. */ if (parent_pdev->no_d3cold) return false;
This is needed to avoid the regression reported in the cover letter, but also allows pre-2015 systems to (still) have the D3cold possibility.
Out of curiosity I looked up an pre-2015 laptop (found Acer V5-573G, apparently from November 2013, Windows 8.1) and extracted the ACPI tables from the BIOS images. BIOS 2.28 (2014/05/13) introduces support for power resources on the parent devicea(_SB.PCI0.PEG0._PR3 and a related NVP3 device) when _OSI("Windows 2013") is true. (This is added as alternative for the old DSM interface.)
Maybe 2014 is also an appropriate cutoff date? I wonder if it is feasible to detect firmware use of _OSI("Windows 2013") and use that instead of the BIOS year.