[PATCH] video/aperture: match the pci device when calling sysfb_disable()

[Javier Martinez Canillas]

Thomas Zimmermann <tzimmermann at suse.de> writes:

Hello Alex and Thomas,

> Hi
>
> Am 16.08.24 um 22:57 schrieb Alex Deucher:
>> On Mon, Aug 12, 2024 at 8:10 AM Thomas Zimmermann <tzimmermann at suse.de> wrote:
>>> Hi
>>>
>>> Am 10.08.24 um 13:44 schrieb kernel test robot:
>>>> Hi Alex,
>>>>
>>>> kernel test robot noticed the following build errors:
>>>>
>>>> [auto build test ERROR on drm-misc/drm-misc-next]
>>>> [also build test ERROR on linus/master v6.11-rc2 next-20240809]
>>>> [If your patch is applied to the wrong git tree, kindly drop us a note.
>>>> And when submitting patch, we suggest to use '--base' as documented in
>>>> https://git-scm.com/docs/git-format-patch#_base_tree_information]
>>>>
>>>> url:    https://github.com/intel-lab-lkp/linux/commits/Alex-Deucher/video-aperture-match-the-pci-device-when-calling-sysfb_disable/20240810-021357
>>>> base:   git://anongit.freedesktop.org/drm/drm-misc drm-misc-next
>>>> patch link:    https://lore.kernel.org/r/20240809150327.2485848-1-alexander.deucher%40amd.com
>>>> patch subject: [PATCH] video/aperture: match the pci device when calling sysfb_disable()
>>>> config: csky-randconfig-001-20240810 (https://download.01.org/0day-ci/archive/20240810/202408101951.tXyqYOzv-lkp@intel.com/config)
>>>> compiler: csky-linux-gcc (GCC) 14.1.0
>>>> reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20240810/202408101951.tXyqYOzv-lkp@intel.com/reproduce)
>>>>
>>>> If you fix the issue in a separate patch/commit (i.e. not just a new version of
>>>> the same patch/commit), kindly add following tags
>>>> | Reported-by: kernel test robot <lkp at intel.com>
>>>> | Closes: https://lore.kernel.org/oe-kbuild-all/202408101951.tXyqYOzv-lkp@intel.com/
>>>>
>>>> All errors (new ones prefixed by >>):
>>>>
>>>>      csky-linux-ld: drivers/video/aperture.o: in function `aperture_remove_conflicting_pci_devices':
>>>>>> aperture.c:(.text+0x222): undefined reference to `screen_info_pci_dev'
>>> Strange. There's a already placeholder [1] for architectures without
>>> PCI. Otherwise the source file is listed at [2].
>> So I dug into this, and the problem seems to be that
>> CONFIG_SCREEN_INFO is not defined in that config.  I can't figure out
>> how this should work in that case or why this is not a problem in
>> drivers/firmware/sysfb.c.
>>
>> Something like this works:
>> diff --git a/drivers/video/aperture.c b/drivers/video/aperture.c
>> index 56a5a0bc2b1af..50e98210c9fe5 100644
>> --- a/drivers/video/aperture.c
>> +++ b/drivers/video/aperture.c
>> @@ -347,7 +347,9 @@ EXPORT_SYMBOL(__aperture_remove_legacy_vga_devices);
>>    */
>>   int aperture_remove_conflicting_pci_devices(struct pci_dev *pdev,
>> const char *name)
>>   {
>> +#if defined(CONFIG_SCREEN_INFO)
>>          struct screen_info *si = &screen_info;
>> +#endif
>>          bool primary = false;
>>          resource_size_t base, size;
>>          int bar, ret = 0;
>> @@ -355,8 +357,10 @@ int
>> aperture_remove_conflicting_pci_devices(struct pci_dev *pdev, const
>> char *na
>>          if (pdev == vga_default_device())
>>                  primary = true;
>>
>> +#if defined(CONFIG_SCREEN_INFO)
>>          if (pdev == screen_info_pci_dev(si))
>>                  sysfb_disable();
>> +#endif
>>
>>          for (bar = 0; bar < PCI_STD_NUM_BARS; ++bar) {
>>                  if (!(pci_resource_flags(pdev, bar) & IORESOURCE_MEM))
>>
>> But that can't be the right fix...  Any ideas?
>
> Thanks for investigating. I'd say we should pass the device (pdev->dev) 
> to sysfb_disable() and  do the test there. In sysfb.c, next to 
> sysfb_disable(), you'll find sysfb_parent_dev(), which gives the Linux 
> device of the screen_info.
>
> The code then looks something like this:
>
> sysfb_disable(struct device *dev)
> {
>      if (dev && dev == sysfb_parent_dev(screen_info))
>        return
>
>    /* else do the current code */
> }
>
> there's an invocation of sysfb_disable() in drivers/of/platform.c where 
> you can pass NULL.
>

Agreed. That sounds like the best approach.

> Best regards
> Thomas
>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat