W dniu 16.02.2024 o 21:51, Rafael J. Wysocki pisze: > On Fri, Feb 16, 2024 at 9:20 PM Mateusz Jończyk <mat.jonczyk@xxxxx> wrote: >> W dniu 16.02.2024 o 19:49, Bjorn Helgaas pisze: >>> On Fri, Feb 16, 2024 at 07:26:06PM +0100, Rafael J. Wysocki wrote: >>>> On Tue, Dec 26, 2023 at 1:50 PM Mateusz Jończyk <mat.jonczyk@xxxxx> wrote: >>>>> 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. [snip] >>> And neither of the two _PRT entries yields a working i801 device? >> Unpatched Linux uses the first matching entry, but the second one gives >> a working i801 device. The point is to print a warning message to see >> how many devices are affected and whether it is safe to switch the code >> to use the last matching entry in all instances. >> >> Therefore I used dev_warn(). > I don't quite see a connection between the above and the log level. OK, so I'll use dev_info() then. Greetings, Mateusz
