On 31.8.2020 9.52, Nehal Bakulchandra Shah wrote: > From: Nehal Bakulchandra Shah <Nehal-Bakulchandra.shah@xxxxxxx> > > On some platform of AMD, S3 fails with HCE and SRE errors.To fix this, > sparse controller enable bit has to be disabled. > > Signed-off-by: Nehal Bakulchandra Shah <Nehal-Bakulchandra.shah@xxxxxxx> > --- > drivers/usb/host/xhci-pci.c | 12 ++++++++++++ > drivers/usb/host/xhci.h | 1 + > 2 files changed, 13 insertions(+) > > diff --git a/drivers/usb/host/xhci-pci.c b/drivers/usb/host/xhci-pci.c > index 3feaafebfe58..865a16e6c1ed 100644 > --- a/drivers/usb/host/xhci-pci.c > +++ b/drivers/usb/host/xhci-pci.c > @@ -160,6 +160,9 @@ static void xhci_pci_quirks(struct device *dev, struct xhci_hcd *xhci) > (pdev->device == 0x15e0 || pdev->device == 0x15e1)) > xhci->quirks |= XHCI_SNPS_BROKEN_SUSPEND; > > + if (pdev->vendor == PCI_VENDOR_ID_AMD && pdev->device == 0x15e5) > + xhci->quirks |= XHCI_DISABLE_SPARSE; > + > if (pdev->vendor == PCI_VENDOR_ID_AMD) > xhci->quirks |= XHCI_TRUST_TX_LENGTH; > > @@ -371,6 +374,15 @@ static int xhci_pci_probe(struct pci_dev *dev, const struct pci_device_id *id) > /* USB 2.0 roothub is stored in the PCI device now. */ > hcd = dev_get_drvdata(&dev->dev); > xhci = hcd_to_xhci(hcd); > + > + if (xhci->quirks & XHCI_DISABLE_SPARSE) { > + u32 reg; > + > + reg = readl(hcd->regs + 0xC12C); > + reg &= ~BIT(17); > + writel(reg, hcd->regs + 0xC12C); > + } > + Is disabling the bit once in probe enough? xHC will be reset after hibernation as well, does this bit need to be cleared after that? Also consider turning this into a separate function with a proper description, see xhci_pme_quirk() for example. Avoids cluttering probe. Actually if this bit only needs to be cleared once then that function could be called from xhci_pci_setup() -Mathias