On Fri, Jul 08, 2016 at 01:38:27AM +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 (on a Clevo P651RA, GTX965M). > > 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. > > pci_d3cold_disable() is not used because on some machines, the old DSM > method is broken. On a Lenovo T440p (GT 730M) memory and disk corruption > would occur, but that is fixed with this patch[2].
Fair enough. > [1]: > https://msdn.microsoft.com/windows/hardware/drivers/bringup/firmware-requirements-for-d3cold > [2]: > https://github.com/Bumblebee-Project/bbswitch/issues/78#issuecomment-223549072 > > v2: simply check directly for _PR3. Added affected machines. > > Signed-off-by: Peter Wu <peter at lekensteyn.nl> One nitpick below but otherwise looks reasonable to me. Reviewed-by: Mika Westerberg <mika.westerberg at linux.intel.com> BTW, thanks for doing this :) > --- > drivers/gpu/drm/nouveau/nouveau_acpi.c | 33 +++++++++++++++++++++++++++++---- > 1 file changed, 29 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c > b/drivers/gpu/drm/nouveau/nouveau_acpi.c > index ad273ad..38a6445 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; > @@ -212,9 +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. */ You should follow standard block comment style here. > +static bool nouveau_pr3_present(struct pci_dev *pdev) > +{ > + struct pci_dev *parent_pdev = pci_upstream_bridge(pdev); > + struct acpi_device *parent_adev; > + > + if (!parent_pdev) > + return false; > + > + parent_adev = ACPI_COMPANION(&parent_pdev->dev); > + if (!parent_adev) > + return false; > + > + return acpi_has_method(parent_adev->handle, "_PR3"); > +}
