On 4/23/21 10:37 AM, Alex Williamson wrote:
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On Fri, 23 Apr 2021 11:12:05 -0400
Sinan Kaya <okaya@xxxxxxxxxx> wrote:
+Alex,
On 4/23/2021 10:54 AM, Shanker Donthineni wrote:
+static int reset_nvidia_gpu_quirk(struct pci_dev *dev, int probe)
+{
+#ifdef CONFIG_ACPI
+ acpi_handle handle = ACPI_HANDLE(&dev->dev);
+
+ /*
+ * Check for the affected devices' ID range. If device is not in
+ * the affected range, return -ENOTTY indicating no device
+ * specific reset method is available.
+ */
+ if ((dev->device & 0xffc0) != 0x2340)
+ return -ENOTTY;
+
+ /*
+ * Return -ENOTTY indicating no device-specific reset method if _RST
+ * method is not defined
+ */
+ if (!handle || !acpi_has_method(handle, "_RST"))
+ return -ENOTTY;
+
+ /* Return 0 for probe phase indicating that we can reset this device */
+ if (probe)
+ return 0;
+
+ /* Invoke _RST() method to perform the device-specific reset */
+ if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) {
+ pci_warn(dev, "Failed to reset the device\n");
+ return -EINVAL;
+ }
+ return 0;
+#else
+ return -ENOTTY;
+#endif
+}
Interesting, some pieces of this function (especially the ACPI _RST)
could be generalized.
Agreed, we should add a new function level reset method for this rather
than a device specific reset. At that point the extent of the device
specific quirk could be to restrict SBR.
Thanks Sinan/Alex, Agree ACPI _RST is a generic method applicable
to all PCI-ACPI-DEVICE objects. I'll define a new helper function
pci_dev_acpi_reset() and move common code to it. I've one question
before posting a v2 patch, should I call pci_dev_acpi_reset() from
the reset_nvidia_gpu_quirk() or always apply _RST method if exists?
Option-1:
static int reset_nvidia_gpu_quirk(struct pci_dev *dev, int probe)
{
/* Check for the affected devices' ID range */
if ((dev->device & 0xffc0) != 0x2340)
return -ENOTTY;
return pci_dev_acpi_reset(dev, probe);
}
OR
Option-2
int pci_dev_specific_reset(struct pci_dev *dev, int probe)
{
const struct pci_dev_reset_methods *i;
if (!pci_dev_acpi_reset(dev, probe))
return 0;
...
}
It'd be useful to know what
these devices are (not in pciids yet), why we expect to only see them in
specific platforms (embedded device?), and the failure mode of the SBR.
These are not plug-in PCIe GPU cards, will exist on upcoming
server baseboards. Triggering SBR without firmware notification
would leave the device inoperable for the current system boot.
It requires a system hard-reboot to get the GPU device back to
normal operating condition post-SBR.
Thanks,
Alex
