Unable to build driver

[Azulath]

When trying to build the driver it aborts with the following error in the log:

/var/lib/dkms/rtl88x2bu/5.2.4.4/build/hal/hal:hci/hal_usb.c:28:8: error: cast between incompatible function types from 'void (*)(void *)' to 'void (*) (long unsigned int)' [-Werror=cast function type]
(void(*)(unsigned long))usb_revc_tasklet,

I'm running Fedora 28 with Linux 4.17.12

[cilynx]

Can you provide the entire build log, please?

[Azulath]

Sure thing, there you go and thanks for taking the time:
https://pastebin.com/yetrUFHi

[cilynx]

Thanks -- I'll do some digging. I found someone else with the same issue on 4.17.5-1-zen (x86_64).

http://pastebin.calculate-linux.org/ru/show/63918

It's interesting because it builds clean for me on Debian's 4.17.8-1. I'll ping back here if I come up with anything useful.

[Azulath]

Thanks. Could it be because of the newer Kernel? 4.17.12-200.fc28 vs 4.17.8-1

[cilynx]

Normally, I'd say yes, but the fact that someone with 4.17.5-1-zen is running into the exact same error as you makes it tricky. The issue looks to be some complication around a void pointer. I'm looking around to see if anything has changed around that stuff recently and if maybe some vendors have patched early or held off.

[cilynx]

What version of gcc are you using?

[Azulath]

I'm using gcc version 8.1.1 20180712 (Red Hat 8.1.1-5) (GCC)

[Azulath]

Any news on that front?

I'm asking because I could still refund this WiFi stick and if it stays unusable I probably will.

[MaxG87]

This is not an error but an warning. It fails to compile only due to the -Werror flag. The compile should work if you comment out the line containing -Werror in the Makefile.

I could imagine that the problem arises due to different kernel patches applied by different distributions. On my system, the tasklet_init function seems to be defined in

/usr/src/linux-headers-4.17.0-3-common/include/linux/interrupt.h

and the signature is

extern void tasklet_init(struct tasklet_struct *t, void (*func)(unsigned long), unsigned long data)

which is the appropriate typing for the usage in hal_usb.c. Maybe you could check your interrupt.h. Then, at least, we would know the source of the error.

[Azulath]

Thanks for your response, but as mentioned above I've already sent the stick back and picked a new one with an Artheros chipset.

[Cyb0org]

/usr/src/rtl88x2bu-5.2.4.4/hal/hal_hci/hal_usb.c: In function ‘usb_init_recv_priv’:
/usr/src/rtl88x2bu-5.2.4.4/hal/hal_hci/hal_usb.c:28:8: warning: cast between incompatible function types from ‘void ()(void )’ to ‘void ()(long unsigned int)’ [-Wcast-function-type]
(void()(unsigned long))usb_recv_tasklet,
^

/usr/src/rtl88x2bu-5.2.4.4/hal/rtl8822b/usb/rtl8822bu_xmit.c: In function ‘rtl8822bu_init_xmit_priv’:
/usr/src/rtl88x2bu-5.2.4.4/hal/rtl8822b/usb/rtl8822bu_xmit.c:843:8: warning: cast between incompatible function types from ‘void ()(void )’ to ‘void ()(long unsigned int)’ [-Wcast-function-type]
(void()(unsigned long))rtl8822bu_xmit_tasklet,
^

tasklet_init from "/usr/src/linux-headers-4.18.0-10/include/linux/interrupt.h":

extern void tasklet_init(struct tasklet_struct *t,
void (*func)(unsigned long), unsigned long data);

Ubuntu 18.10
gcc version 8.2.0 (Ubuntu 8.2.0-7ubuntu1)

I think #3 and #5 are about the same problem.

[silibot]

I have Ubuntu 18.10 and kernel 4.18.0-11 and using @MaxG87's suggestion of commenting out the line containing -Werror in the Makefile I was able to build and install the module successfully. After a reboot and logging in I plugged it in and now it is working again! Thank you sir.