On 6/15/21 7:36 AM, Hans Verkuil wrote:
Hi Shuah,
On 11/06/2021 03:58, Shuah Khan wrote:
Smatch static checker warns that "mdev" can be null:
sound/usb/media.c:287 snd_media_device_create() warn: 'mdev' can also be NULL
If CONFIG_MEDIA_CONTROLLER is disabled, this file should not be included in the build.
The below conditions in the sound/usb/Makefile are in place to ensure that media.c isn't included in the build.
sound/usb/Makefile: snd-usb-audio-$(CONFIG_SND_USB_AUDIO_USE_MEDIA_CONTROLLER) += media.o
select SND_USB_AUDIO_USE_MEDIA_CONTROLLER if MEDIA_CONTROLLER && (MEDIA_SUPPORT=y || MEDIA_SUPPORT=SND_USB_AUDIO)
The following config check in include/media/media-dev-allocator.h is in place to enable the API only when CONFIG_MEDIA_CONTROLLER and CONFIG_USB are enabled.
#if defined(CONFIG_MEDIA_CONTROLLER) && defined(CONFIG_USB)
This check doesn't work as intended when CONFIG_USB=m. When CONFIG_USB=m, CONFIG_USB_MODULE is defined and CONFIG_USB is not. The above config check doesn't catch that CONFIG_USB is defined as a module and disables the API. This results in sound/usb enabling Media Controller specific ALSA driver code, while Media disables the Media Controller API.
Fix the problem requires two changes:
Change the check to use IS_ENABLED to detect when CONFIG_USB is enabled as a module or static. Since CONFIG_MEDIA_CONTROLLER is a bool, leave the check unchanged to be consistent with drivers/media/Makefile.
Change the drivers/media/mc/Makefile to include mc-dev-allocator.o in mc-objs when CONFIG_USB is y or m.
If I test this patch, then I get:
drivers/media/mc/mc-dev-allocator.c:97:22: error: redefinition of 'media_device_usb_allocate' 97 | struct media_device *media_device_usb_allocate(struct usb_device *udev, | ^~~~~~~~~~~~~~~~~~~~~~~~~ In file included from drivers/media/mc/mc-dev-allocator.c:24: include/media/media-dev-allocator.h:55:36: note: previous definition of 'media_device_usb_allocate' was here 55 | static inline struct media_device *media_device_usb_allocate( | ^~~~~~~~~~~~~~~~~~~~~~~~~ drivers/media/mc/mc-dev-allocator.c:119:6: error: redefinition of 'media_device_delete' 119 | void media_device_delete(struct media_device *mdev, const char *module_name, | ^~~~~~~~~~~~~~~~~~~ In file included from drivers/media/mc/mc-dev-allocator.c:24: include/media/media-dev-allocator.h:59:20: note: previous definition of 'media_device_delete' was here 59 | static inline void media_device_delete( | ^~~~~~~~~~~~~~~~~~~
The .config has:
# CONFIG_USB_SUPPORT is not set CONFIG_MEDIA_CONTROLLER=y
Hans,
Can you share your full config with me?
thanks, -- Shuah