NVIDIA and nouveau

Posted Oct 6, 2022 8:31 UTC (Thu) by marcH (subscriber, #57642)
Parent article: NVIDIA and nouveau

> he has wondered if there might be a way to delay firmware loading until after the real root filesystem is mounted, but has not really worked that out yet.

Discussed in 2016:
https://lkml.iu.edu/hypermail/linux/kernel/1609.0/01530.html

https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/354089/3#message-6133ed6092de59e5a21cb25df03bdf1278a724d1

NVIDIA and nouveau

Posted Oct 10, 2022 9:05 UTC (Mon) by tiwai (subscriber, #39450) [Link]

Interesting that such a problem hasn't been solved yet.

I guess the easiest solution for now is to re-use the existing UMH of the firmware loader; basically you just need to enable CONFIG_FW_LOADER_USER_HELPER (but turn off CONFIG_FW_LOADER_USER_HELPER_FALLBACK), and modify / create a new helper to call request_firmware*() with FW_OPT_USERHELPER flag to allow the fallback via sysfs interface if the target firmware isn't found in initrd.
Then you can set up user-space as you like to pass the firmware at any feasible moment with a classic mechanism via sysfs. Systems without an extra setup would keep working as long as a target firmware is put in initrd, too (just like now).