Re: [PATCH 0/5] staging: vc04_services: Address module cleanup

[Umang Jain <umang.jain@ideasonboard.com>]

Hi Stefan,

On 17/03/24 5:38 pm, Stefan Wahren wrote:
> Hi Umang,
>
> Am 15.03.24 um 11:56 schrieb Umang Jain:
>> The series addresses the following TODO item:
>>
>> ```
>> * Fix kernel module support
>>
>> Even the VPU firmware doesn't support a VCHI re-connect, the driver
>> should properly handle a module unload. This also includes that all
>> resources must be freed (kthreads, debugfs entries, ...) and global
>> variables avoided.
>> ```
>>
>> Patch 1/5 to 3/5 are log cleanups spotted during the reading of the
>> driver.
>>
>> Patch 4/5 implements .remove() function vptr so that individual
>> devices(bcm2835-audio, bcm2835-camera, bcm2835-isp etc.)
>> can run their cleanup when removed from the vchiq_bus, during their
>> own module unload.
>>
>> Patch 5/5 stops the kthreads started by vchiq - on shutdown path.
>>
>> Rest of the module cleanup (debugfs entries, deregister char device
>> etc.) is already done as part of vchiq_remove().
>
> great work!

:-)
>
>>
>> Testing on RPi4 for vchiq module unload:
>>
>> ```
>> uajain@ATX:~$ uname -r
>> 6.8.0-rc1-00128-gab2b09f632fa-dirty
>> uajain@ATX:~$ dmesg | grep vchiq
>> [   21.401426] vchiq: module is from the staging directory, the 
>> quality is unknown, you have been warned.
>> uajain@ATX:~$ sudo modprobe bcm2835_mmal_vchiq
>> sudo: unable to resolve host ATX: Temporary failure in name resolution
>> uajain@ATX:~$ dmesg | grep vchiq
>> [   21.401426] vchiq: module is from the staging directory, the 
>> quality is unknown, you have been warned.
>> [   96.388148] bcm2835_mmal_vchiq: module is from the staging 
>> directory, the quality is unknown, you have been warned.
>> uajain@ATX:~$ lsmod | grep vchiq
>> bcm2835_mmal_vchiq     40960  0
>> vchiq                 581632  1 bcm2835_mmal_vchiq
>> uajain@ATX:~$ sudo rmmod bcm2835_mmal_vchiq vchiq
>> sudo: unable to resolve host ATX: Temporary failure in name resolution
>> uajain@ATX:~$ lsmod | grep vchiq
>> uajain@ATX:~$ dmesg | grep vchiq
>> [   21.401426] vchiq: module is from the staging directory, the 
>> quality is unknown, you have been warned.
>> [   96.388148] bcm2835_mmal_vchiq: module is from the staging 
>> directory, the quality is unknown, you have been warned.
>> uajain@ATX:~$
>
> What happens if you run "sudo modprobe bcm2835_mmal_vchiq" again?

Just seeing this right now - at bottom of the mail thread.

So trying to re-load the module fails :

[  207.665281] bcm2835_vchiq fe00b840.mailbox: failed to set channelbase 
(response: ffffffff)
[  207.674245] bcm2835_vchiq fe00b840.mailbox: arm: Could not initialize 
vchiq platform
[  223.527580] bcm2835_mmal_vchiq: module is from the staging directory, 
the quality is unknown, you.
[  223.539469] bcm2835_mmal_vchiq: unknown parameter 'vchiq' ignored

which is known as vchiq doesn't support re-connect.