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

Thomas Zimmermann <tzimmermann@xxxxxxx> · Mon, 19 Aug 2024 10:04:22 +0200

Hi

Am 16.08.24 um 22:57 schrieb Alex Deucher:
On Mon, Aug 12, 2024 at 8:10 AM Thomas Zimmermann <tzimmermann@xxxxxxx> 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@xxxxxxxxx/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@xxxxxxxxx/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@xxxxxxxxx>
| Closes: https://lore.kernel.org/oe-kbuild-all/202408101951.tXyqYOzv-lkp@xxxxxxxxx/

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.

Best regards
Thomas


Alex

[1]
https://elixir.bootlin.com/linux/v6.10/source/include/linux/screen_info.h#L127
[2] https://elixir.bootlin.com/linux/v6.10/source/drivers/video/Makefile#L11

Best regards
Thomas

     csky-linux-ld: drivers/video/aperture.o: in function `devm_aperture_acquire_release':
aperture.c:(.text+0x2c0): undefined reference to `screen_info'
csky-linux-ld: aperture.c:(.text+0x2c4): undefined reference to `screen_info_pci_dev'
--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)


--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)







