On 02/08/2013 03:07 AM, Samuel Ortiz wrote: > On Fri, Feb 08, 2013 at 02:36:16AM -0800, Darren Hart wrote: >> On 02/08/2013 12:49 AM, Samuel Ortiz wrote: >>>> Well, this happens when the driver in question gets removed by another >>>> driver. >>> removed by another driver ? I'm not sure I understand what that means. >> >> In my case, the gpio-sch probe function runs and creates the gpiochip >> with 14 GPIO lines. Later lpc-sch probe runs, > That's weird: The lpc-sch probe should run first. Then the gpio-sch probe > should be called when lpc-sch adds the MFD cells as platform devices, from > lpc_sch_probe(). > So someone is adding gpio-sch as a platform device, and that is wrong. > >> adds devices to the mfd >> device list, fails the WDT base address as described below, and then >> removes the devices in the mfd device list, which triggers the removal >> of the gpio-sch device. >> >> If I just skip the WDT lookup and not abort, then things work as I had >> expected. Sooo... does it make sense to remove ALL the MFD device when >> the read of the WDTBA registers indicates "Disabled"? Seems extreme to me. > Yes, that's a bit rough. But I think you have a more fundamental problem where > you're probing both LPC and your GPIO driver. > >>>> Samuel, does it make sense for CONFIG_GPIO_SCH to require >>>> CONFIG_LPC_SCH? I'm building for a Queensbay (Atom E6xx + EG20T PCH). >>>> There is no SCH as I understand things. Can these be decoupled? >>> They actually don't have code dependency, GPIO_SCH selects LPC_SCH beacause >>> the MFD parts actually creates the GPIO device. >>> So you're saying Queensbay use the same GPIO IP block without actually >>> having >>> SCH ? >> >> That is how I currently understand it. These drivers appear to have been >> originaly written for the Silverthorne (Z5xx) CPUs and the Intel SCH >> chipset. > If your lpc_sch_probe routine runs, you basically have an LPC on your PCI bus > here. As I said, PCI probes lpc_sch _and_ gpio_sch is probed as well (As a > platform device, probably coming from your SFI tables or so). Probing both is > problematic, especially since you do have an LPC sitting on your PCI bus.
Upon closer inspection what is really happening is the lpc_sch probe runs and adds the sch_gpio device with the mfd_add_devices call which creates the platform device. At that time the gpio_sch probe runs and sets up the gpio stuff. Control returns to the lpc_sch which then tries to find the WDT, fails, and removes all the mfd devices it had added previously. I'm working with firmware (UEFI, ACPI - not SFI) on why WDTBA is 0, but in the meantime I'll work up a patch to not destroy all the valid devices when that one fails. -- Darren Hart Intel Open Source Technology Center Yocto Project - Technical Lead - Linux Kernel -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/