I've been trying to debug a problem with my driver (drivers/input/misc/winbond-cir.c) and suspend/resume. If the driver is loaded, my test computer (Intel DG45FC motherboard) survives one suspend/resume cycle but hangs (no pings, no magic sysrq, etc) on the second suspend attempt (tested on 2.6.32.X and currently testing on a git checkout from yesterday). After sprinkling a lot of printk's everywhere, it seems that the kernel freezes either in the below call, or at a random time soon after it: drivers/pnp/driver.c:pnp_bus_suspend(), calls pnp_dev->protocol->suspend() Since this is a pnpacpi device, that is a call to: drivers/pnp/pnpacpi/core.c:pnpacpi_disable_resources(), which calls the ACPI "_DIS" method for the "UAR3" object. Now, if I add a hack to my driver to remove the PNP_DISABLE flag from device->capabilities (which means, AFAIK, that the above ACPI "_DIS" method won't get called during suspend), I can reliably suspend and resume, which is why I believe that this has got something to do with ACPI even though the crash during suspend doesn't always happen while "my" drivers _DIS method is being executed. I've tried debugging the ACPI method by doing: echo _DIS >> /sys/module/acpi/parameters/trace_method_name echo enable >> /sys/module/acpi/parameters/trace_state and done a suspend/resume/suspend (i.e. caused the system to crash) while capturing the output via netconsole. I can't derive any interesting insights from the log though. The decompiled dsdt table and the log capture from netconsole is attached....the first suspend starts at 203.176799 (the first line of the log) and ends around 209.083233 (line 2576), the resume starts right after the suspend and ends around 211.358430 (line 2712), the second suspend starts at 342.876299 (line 2718) and ends where the log file ends (with a freeze). I'll add the log and dsdt to this bug report...
Created attachment 24949 [details] debug log captured by netconsole during suspend/resume/suspend
Created attachment 24950 [details] decompiled dsdt
Sorry - semi automatic adding of maintainer backfired given who filed the bug itself
I'm just getting more and more confused in trying to debug this...if I insert this: if (1) { struct acpi_device *acpi_dev = device->data; acpi_handle handle = acpi_dev->handle; char prefix[80] = {'\0'}; struct acpi_buffer buffer = {sizeof(prefix), prefix}; acpi_get_name(handle, ACPI_FULL_PATHNAME, &buffer); printk("Calling _DIS on %s (0x%p)\n", prefix, handle); acpi_dbg_level=0xFFFFFFFF; printk("_DIS first attempt\n"); if (ACPI_FAILURE(acpi_evaluate_object(handle, "_DIS", NULL, NULL))) printk("Calling _DIS once Failed\n"); printk("_DIS second attempt\n"); if (ACPI_FAILURE(acpi_evaluate_object(handle, "_DIS", NULL, NULL))) printk("Calling _DIS twice Failed\n"); acpi_dbg_level=0x3; } at random places in my driver's probe method, it seems to work as long as it's placed before the request_irq() call, whenever it's after the request_irq() call, the machine hangs... But looking at the "_DIS" method from the dsdt...all it does (as far as I can tell) is: 1) Acquire mutex 2) Set logical device number in SuperIO chip 3) Write a disable bit at 0x30 4) Release mutex So why would the request_irq() call have any bearing on "_DIS"....???
Answer: Because calling _DIS immediately generates an IRQ with all status bits set...would the proper fix be to use disable_irq() / enable_irq() at the right places (suspend/resume) in the driver?
Patch sent to linux-input and linux-kernel
please attach the url to this patch. re-assign to linux-input category.
Patch URL added...
Fixed with commit 197d4db752e67160d79fed09968c2140376a80a3