Re: [LKP] [lkp] [gpio] 3c702e9987: kmsg.user_verbs:couldn't_register_device_number

[Linus Walleij]

On Mon, Feb 15, 2016 at 3:39 AM, Huang, Ying <ying.huang@xxxxxxxxx> wrote:
> Michael Welling <mwelling@xxxxxxxx> writes:

>> Could you run cat /proc/devices?
>
> Sorry, the test mechanism is not flexible enough to run some shell
> command in test system.  Could you provide a specialized debug kernel to
> dump the necessary information in kernel log?  We can collect dmesg
> easily.

Can you try this:

diff --git a/fs/char_dev.c b/fs/char_dev.c
index 24b142569ca9..74a2d433273e 100644
--- a/fs/char_dev.c
+++ b/fs/char_dev.c
@@ -96,6 +96,8 @@ __register_chrdev_region(unsigned int major,
unsigned int baseminor,
             goto out;
         }
         major = i;
+        pr_info("CHARDEV: allocate major %d for \"%s\"\n",
+            i, name);
     }

     cd->major = major;

Then dmesg |grep CHARDEV should tell what we need to know.

Yours,
Linus Walleij