[PATCH 3/3] drm/panthor: Fix undefined panthor_device_suspend/resume symbol issue

[Robin Murphy]

On 2024-03-11 11:52 am, Boris Brezillon wrote:
> On Mon, 11 Mar 2024 13:49:56 +0200
> Jani Nikula <jani.nikula at linux.intel.com> wrote:
> 
>> On Mon, 11 Mar 2024, Boris Brezillon <boris.brezillon at collabora.com> wrote:
>>> On Mon, 11 Mar 2024 13:05:01 +0200
>>> Jani Nikula <jani.nikula at linux.intel.com> wrote:
>>>   
>>>> This breaks the config for me:
>>>>
>>>>    SYNC    include/config/auto.conf.cmd
>>>>    GEN     Makefile
>>>> drivers/iommu/Kconfig:14:error: recursive dependency detected!
>>>> drivers/iommu/Kconfig:14:	symbol IOMMU_SUPPORT is selected by DRM_PANTHOR
>>>> drivers/gpu/drm/panthor/Kconfig:3:	symbol DRM_PANTHOR depends on PM
>>>> kernel/power/Kconfig:183:	symbol PM is selected by PM_SLEEP
>>>> kernel/power/Kconfig:117:	symbol PM_SLEEP depends on HIBERNATE_CALLBACKS
>>>> kernel/power/Kconfig:35:	symbol HIBERNATE_CALLBACKS is selected by XEN_SAVE_RESTORE
>>>> arch/x86/xen/Kconfig:67:	symbol XEN_SAVE_RESTORE depends on XEN
>>>> arch/x86/xen/Kconfig:6:	symbol XEN depends on PARAVIRT
>>>> arch/x86/Kconfig:781:	symbol PARAVIRT is selected by HYPERV
>>>> drivers/hv/Kconfig:5:	symbol HYPERV depends on X86_LOCAL_APIC
>>>> arch/x86/Kconfig:1106:	symbol X86_LOCAL_APIC depends on X86_UP_APIC
>>>> arch/x86/Kconfig:1081:	symbol X86_UP_APIC prompt is visible depending on PCI_MSI
>>>> drivers/pci/Kconfig:39:	symbol PCI_MSI is selected by AMD_IOMMU
>>>> drivers/iommu/amd/Kconfig:3:	symbol AMD_IOMMU depends on IOMMU_SUPPORT
>>>
>>> Uh, I guess we want a "depends on IOMMU_SUPPORT" instead of "select
>>> IOMMU_SUPPORT" in panthor then.
>>
>> That works for me.
> 
> Let's revert the faulty commit first. We'll see if Steve has a
> different solution for the original issue.

FWIW, the reasoning in the offending commit seems incredibly tenuous. 
There are far more practical reasons for building an arm/arm64 kernel 
without PM - for debugging or whatever, and where one may even still 
want a usable GPU, let alone just a non-broken build - than there are 
for building this driver for x86. Using pm_ptr() is trivial, and if you 
want to support COMPILE_TEST then there's really no justifiable excuse 
not to.

Thanks,
Robin.