From: Dmitry Baryshkov <email@example.com> To: Rob Clark <firstname.lastname@example.org> Cc: John Stultz <email@example.com>, Bjorn Andersson <firstname.lastname@example.org>, Vinod Koul <email@example.com>, Srini Kandagatla <firstname.lastname@example.org>, Amit Pundir <email@example.com>, YongQin Liu <firstname.lastname@example.org>, linux-arm-msm <email@example.com> Subject: Re: Regression: arm64: dts: sdm845-db845c: make firmware filenames follow linux-firmware Date: Wed, 5 May 2021 23:07:12 +0300 [thread overview] Message-ID: <CAA8EJppY6Qnnc5n9=D-bvb44-=U0b3ZefeOvTW7xOoKPLbgY3Q@mail.gmail.com> (raw) In-Reply-To: <CAF6AEGvZMe5BTBtu+=koAeDQF9AKDa0CTEWJTSV8+CW2jsh7fA@mail.gmail.com> On Wed, 5 May 2021 at 23:01, Rob Clark <firstname.lastname@example.org> wrote: > > On Wed, May 5, 2021 at 12:35 PM John Stultz <email@example.com> wrote: > > > > On Wed, May 5, 2021 at 8:04 AM Rob Clark <firstname.lastname@example.org> wrote: > > > On Tue, May 4, 2021 at 11:37 PM John Stultz <email@example.com> wrote: > > > > Hey Dmitry, Bjorn, > > > > I wanted to raise a regression I caught in the merge window on db845c. > > > > > > > > I was seeing troubles with audio and while there are a few other > > > > pending fixes needed, they did not seem to work for me. So I spent > > > > some time bisecting things down and found the problematic commit was > > > > 7443ff06da45 ("arm64: dts: sdm845-db845c: make firmware filenames > > > > follow linux-firmware"). > > > > > > > > It seems for systems using the old firmware filenames, this will break > > > > dependent devices on adsp_pas and cdsp_pas nodes. > > > > > > > > Now, obviously updating the firmware files in userland should resolve > > > > this, but it adds the complexity that we can't just replace the > > > > firmware files because older LTS kernels will look for the old names, > > > > while newer kernels will look for the new names. We can add both files > > > > to the system images, but then there is some confusion on which > > > > version of the firmware files are being used where. > > > > > > > > So yes, we should align with linux-firmware file names, but I think > > > > more care is needed for this sort of thing as it has the potential to > > > > break folks, and this isn't the first time around we've had similar > > > > firmware name changes break us. > > > > > > > > So I'm working on fixing this by including both filenames in userland, > > > > so we probably don't need a revert here, but *please* maybe take more > > > > care on this sort of change. > > > > > > > > > > It is rather more difficult than you think, because if you try the > > > wrong path you could end up waiting with a timeout.. we have > > > shenanigans to work around that for gpu fw in drm/msm to avoid this > > > sort of regression with people using downstream firmware trees. I'd > > > like to rip that out at some point, but I suppose doing so would be > > > problematic for folks doing upstream kernel on android devices. > > > > > > Maybe there is some way to add support to simultaneously > > > request_firmware for two different paths at the same time.. not sure > > > how that would work from the PoV of the usermode helper path. > > > > > > It really is a lot of pain to deal with downstream firmware layout.. > > > > Yeah, but on other platforms, the kernel has to meet and deal with the > > hardware, firmware and userland as it exists in the world. > > It would be quite a thing if an upstream kernel change required a new > > BIOS update which then made the system incompatible with the most > > recent LTS. > > Does downstream exist? :-P > > We first ran into this issue with GPU firmware when it was originally > pushed to linux-firmware. Upstream linux-firmware wanted it moved to > qcom subdirectory. At this point, now upstream and downstream > firmware are incompatible in their directory layout. You can't really > expect the kernel to support the downstream layout but not the > upstream layout. If the upstream kernel has to choose, it will go > with the upstream linux-firmware layout. > > Seriously though, the extra 60sec timeout delays is not an option. I > don't really see any good option other than somehow teaching > request_firmware how to look for two (or multiple) paths at the same > time. I'm not sure (a) if that is possible (ie. without breaking > compatibility with usermode helper), and (b) how others would feel > about adding more complexity to the firmware loader to deal with > downstream firmware trees. If others are open to that idea, I'm all > for it. > > And tbf, the BIOS update example is a *bit* of a stretch, since that > is often not something owners of the hw can do. In this case, it is > just a matter of putting some symlinks in the downstream /lib/firmware > to make it work with both cases. In fact we had this in place for a while for RB5 (qrb5165, sm8250), when there was no official firmware release. -- With best wishes Dmitry
next prev parent reply other threads:[~2021-05-05 20:07 UTC|newest] Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-05-05 6:20 John Stultz 2021-05-05 15:08 ` Rob Clark 2021-05-05 19:35 ` John Stultz 2021-05-05 20:05 ` Rob Clark 2021-05-05 20:07 ` Dmitry Baryshkov [this message] 2021-05-05 21:14 ` John Stultz 2021-05-05 21:02 ` Bjorn Andersson 2021-05-05 18:43 ` Dmitry Baryshkov 2021-05-05 19:06 ` Bjorn Andersson
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