On 10/21/24 8:54 AM, Stephan Gerhold wrote:
+Cc Abel and Johan
FYI, this landed in qcom for-next last week for CRD and T14s.
On Fri, Oct 11, 2024 at 07:16:22PM -0400, Jonathan Marek wrote:
The 3 USB ports on x1e80100-crd are OTG-capable, remove the dr_mode
override to enable OTG.
Signed-off-by: Jonathan Marek <jonathan@xxxxxxxx>
This is a bit problematic, because dr_mode = "otg" seems to imply
gadget/peripheral mode by default and we are currently unable to detect
the role at runtime until the ADSP is started. Being in peripheral mode
by default will break USB installers; they won't be able find the rootfs
via USB. Unfortunately, they wouldn't be able to detect it once in the
rootfs either, because usually you first need to copy the ADSP firmware
from Windows (at least on the laptops).
I think the best quick fix would be to set
role-switch-default-mode = "host";
I have no objection to this but its a hack to workaround qcom's broken
design and perhaps should include a comment along those lines. The
situation is also the same on anything sm8350 and newer.
FYI upstream doesn't support a rootfs on USB because loading a new ADSP
firmware breaks it (cuts off vbus for a moment I guess), but I guess
that doesn't apply to the USB installer case. (maybe the people making
these USB installers should just have to carry a patch with this?)
for now to restore the old behavior in initrd, while still allowing to
switch to peripheral mode once detected by the ADSP later.
It would be nice to have gadget mode in initrd as well, since e.g.
postmarketOS needs that to set up the USB debug shell. But I'm not sure
how we could support that:
- We could designate some of the ports as "peripheral by default" and
some as "host by default". E.g. usb_1_ss0 is also used for EDL and
Fastboot on CRD, so it's more likely to be used in peripheral mode.
But there still would be users confused about why they cannot plug in
their USB installer into one of the ports...
- Long term, I wonder if there is any way we could reuse the reduced
ADSP firmware from UEFI for USB detection until we start the full one
later? Perhaps it provides a similar interface?
This is what I do (minus the "start the full one later" part), with a
hack [1] to make the remoteproc driver skip loading any firmware and
trying to boot the DSP. The UEFI-loaded ADSP firmware has the same
charging/usb functionality as the full ADSP firmware.
[1]
https://github.com/flto/linux/commit/36921742d28b55dc02d8e5a8d6598e567e7874ab
