On Tuesday, June 12, 2018 12:32:34 PM Mikulas Patocka wrote:

On Mon, 4 Jun 2018, kbuild test robot wrote:

quoted

Hi Mikulas,

I love your patch! Perhaps something to improve:

[auto build test WARNING on drm/drm-next]
[also build test WARNING on v4.17-rc7 next-20180601]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Mikulas-Patocka/USB-DisplayLink-patches/20180603-233013

What is it really complaining about? That URL shows 404 Not Found and this 
email has no warnings at all.

screen_base in struct fb_info is annotated with __iomem tag:

...
		char __iomem *screen_base;	/* Virtual address */
...

and this tag should be preserved (or explicitly casted).

quoted

base:   git://people.freedesktop.org/~airlied/linux.git drm-next
reproduce:
        # apt-get install sparse
        make ARCH=x86_64 allmodconfig
        make C=1 CF=-D__CHECK_ENDIAN__

You should be able to reproduce the issue with the above sequence.

quoted

sparse warnings: (new ones prefixed by >>)

[...]

quoted

  1178		u32 old_len = info->fix.smem_len;

quoted

1179		unsigned char *old_fb = info->screen_base;

  1180		unsigned char *new_fb;

[...]

quoted

  1196			if (info->screen_base) {
  1197				memcpy(new_fb, old_fb, old_len);

quoted

1198				dlfb_deferred_vfree(dlfb, info->screen_base);

  1199			}

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics