(removed that big c/c list - kept just media) Em Wed, 25 Mar 2020 16:36:31 -0300 Helen Koike <helen.koike@xxxxxxxxxxxxx> escreveu: > Hello, > > On 3/25/20 1:03 PM, Mauro Carvalho Chehab wrote: > > That's the second part of media Kconfig changes. The entire series is > > at: > > > > https://git.linuxtv.org/mchehab/experimental.git/log/?h=media-kconfig > > I made a quick experiment (using this branch) with someone who works with the kernel for his master degree, but doesn't have much experience in kernel development in general. > I asked him to enable Vimc (from default configs, where multimedia starts disabled). > He knows that Vimc is a virtual camera driver, and this is how he behaved: > > === Start of experiment: > > * He pressed '/' and searched for vimc to see the location path. > * Then he enabled "Multimedia support" and went straight to "Media drivers" (which just shows USB and PCI). > * He went back to "Multimedia support", entered "Media device types" and enabled "Test drivers". > * He went back to "Media drivers" again and didn't find Vimc (nothing changed in this menu). There was an issue with test driver dependencies. this patch fixes it: https://git.linuxtv.org/mchehab/experimental.git/commit/?h=media-kconfig&id=c267c23e0884172beac4fb4e68c35fc26ff2e615 Basically, the VIDEO_DEV was not selected with MEDIA_TEST_SUPPORT. So, the "Media drivers" menu would be empty. After this change, the only thing a .config file would need to build a test driver would either need to select those: CONFIG_MODULES=y CONFIG_MEDIA_SUPPORT=m CONFIG_MEDIA_SUPPORT_FILTER=y CONFIG_MEDIA_TEST_SUPPORT=y CONFIG_V4L_TEST_DRIVERS=y CONFIG_VIDEO_VIMC=y (filtering way) or those: CONFIG_MODULES=y CONFIG_MEDIA_SUPPORT=m CONFIG_VIDEO_DEV=y CONFIG_MEDIA_TEST_SUPPORT=y CONFIG_V4L_TEST_DRIVERS=y CONFIG_VIDEO_VIMC=y (non-filtering way) (MODULES config is optional. I opted to use modules just to be able to use make M=drivers/media) For testing purposes, here, I stored just the above on a file called media_config, and then I did: $ make allnoconfig $ cp media_config >.config $ make olddefconfig && make init 2>/dev/null $ rm $(find drivers/media -name '*.ko') $(find drivers/media -name '*.o') 2>/dev/null $ make M=drivers/media CC [M] drivers/media/common/v4l2-tpg/v4l2-tpg-core.o CC [M] drivers/media/common/videobuf2/videobuf2-core.o ... MODPOST 8 modules ... LD [M] drivers/media/v4l2-core/v4l2-dv-timings.ko LD [M] drivers/media/v4l2-core/videodev.ko In this specific case, either using the filtered or non-filtered way, the number of options to enable "vimc" are the same. Thanks, Mauro
