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 <mat.jonczyk@xxxxx> > Cc: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> > Cc: "Rafael J. Wysocki" <rafael@xxxxxxxxxx> > Cc: Len Brown <lenb@xxxxxxxxxx> > Cc: Borislav Petkov <bp@xxxxxxx> > Cc: Jean Delvare <jdelvare@xxxxxxx> Please, move these (Cc lines) down after --- cutter line. > Previously-reviewed-by: Jean Delvare <jdelvare@xxxxxxx> > Previously-tested-by: Jean Delvare <jdelvare@xxxxxxx> 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
