Tue, Dec 26, 2023 at 01:42:54PM +0100, Mateusz Jończyk kirjoitti:
> On some platforms, the ACPI _PRT function returns duplicate interrupt
> routing entries. Linux uses the first matching entry, but sometimes the
> second matching entry contains the correct interrupt vector.
>
> As a debugging aid, print a warning to dmesg if duplicate interrupt
> routing entries are present. This way, we could check how many models
> are affected.
>
> This happens on a Dell Latitude E6500 laptop with the i2c-i801 Intel
> SMBus controller. This controller is nonfunctional unless its interrupt
> usage is disabled (using the "disable_features=0x10" module parameter).
>
> After investigation, it turned out that the driver was using an
> incorrect interrupt vector: in lspci output for this device there was:
> Interrupt: pin B routed to IRQ 19
> but after running i2cdetect (without using any i2c-i801 module
> parameters) the following was logged to dmesg:
>
> [...]
> i801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
> i801_smbus 0000:00:1f.3: Transaction timeout
> i801_smbus 0000:00:1f.3: Timeout waiting for interrupt!
> i801_smbus 0000:00:1f.3: Transaction timeout
> irq 17: nobody cared (try booting with the "irqpoll" option)
>
> Existence of duplicate entries in a table returned by the _PRT method
> was confirmed by disassembling the ACPI DSDT table.
>
> Windows XP is using IRQ3 (as reported by HWiNFO32 and in the Device
> Manager), which is neither of the two vectors returned by _PRT.
> As HWiNFO32 decoded contents of the SPD EEPROMs, the i2c-i801 device is
> working under Windows. It appears that Windows has reconfigured the
> chipset independently to use another interrupt vector for the device.
> This is possible, according to the chipset datasheet [1], page 436 for
> example (PIRQ[n]_ROUT—PIRQ[A,B,C,D] Routing Control Register).
> [1] https://www.intel.com/content/dam/doc/datasheet/io-controller-hub-9-datasheet.pdf
>
Can you convert this to be a Link tag?
Link: ...URL... # [1]
Signed-off-by: ...
> Signed-off-by: Mateusz Jończyk <[email protected]>
> Cc: Bjorn Helgaas <[email protected]>
> Cc: "Rafael J. Wysocki" <[email protected]>
> Cc: Len Brown <[email protected]>
> Cc: Borislav Petkov <[email protected]>
> Cc: Jean Delvare <[email protected]>
Please, move these (Cc lines) down after --- cutter line.
> Previously-reviewed-by: Jean Delvare <[email protected]>
> Previously-tested-by: Jean Delvare <[email protected]>
This shouldn't be in the commit message, just use the comment block
(after --- line) for this.
..
> struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> struct acpi_pci_routing_table *entry;
> acpi_handle handle = NULL;
> + struct acpi_prt_entry *match = NULL;
> + const char *match_int_source = NULL;
Can you preserve reversed xmas tree ordering?
..
> while (entry && (entry->length > 0)) {
> - if (!acpi_pci_irq_check_entry(handle, dev, pin,
> - entry, entry_ptr))
> - break;
> + struct acpi_prt_entry *curr;
> +
> + if (!acpi_pci_irq_check_entry(handle, dev, pin, entry, &curr)) {
> + if (!match) {
Why not positive condition?
> + match = curr;
> + match_int_source = entry->source;
> + } else {
> + dev_warn(&dev->dev, FW_BUG
> + "ACPI _PRT returned duplicate IRQ routing entries for INT%c: %s[%d] and %s[%d]\n",
> + pin_name(curr->pin),
> + match_int_source, match->index,
> + entry->source, curr->index);
> + /* We use the first matching entry nonetheless,
> + * for compatibility with older kernels.
> + */
> + }
> + }
--
With Best Regards,
Andy Shevchenko