On Wed, Jan 18, 2023 at 5:35 AM Rob Herring <robh+dt@xxxxxxxxxx> wrote: > > On Wed, Jan 18, 2023 at 3:11 AM Dmitry Baryshkov > <dmitry.baryshkov@xxxxxxxxxx> wrote: > > > > Do not create device link for clock controllers. Some of the clocks > > provided to the device via OF can be the clocks that are just parents to > > the clocks provided by this clock controller. Clock subsystem already > > has support for handling missing clock parents correctly (clock > > orphans). Later when the parent clock is registered, clocks get > > populated properly. > > > > An example of the system where this matters is the SDM8450 MTP board > > (see arch/arm64/boot/dts/qcom/sdm845-mtp.dts). Here the dispcc uses > > clocks provided by dsi0_phy and dsi1_phy device tree nodes. However the > > dispcc itself provides clocks to both PHYs, to the PHY parent device, > > etc. With just dsi0_phy in place devlink is able to break the > > dependency, but with two PHYs, dispcc doesn't get probed at all, thus > > breaking display support. > > > > Cc: Bjorn Andersson <andersson@xxxxxxxxxx> > > Cc: Stephen Boyd <sboyd@xxxxxxxxxx> > > Cc: Saravana Kannan <saravanak@xxxxxxxxxx> > > Cc: Abel Vesa <abel.vesa@xxxxxxxxxx> > > Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx> > > --- > > > > This patch has been posted a year ago in January 2022 ([1]). Since that time > > Saravana failed to produce patches to assist in debugging the issue > > ([2]) or to fix the issue ([3]). The issue we observe has been described > > by Abel at ([4]). As we work on adding support for Dual DSI > > configurations, the issue becomes more and more important, since binding > > the whole display subsystem fails. I did send out a patch series[1] to try and fix this. Heck I even talked about this in LPC 2022. So I don't think it's accurate to say I didn't help debug this or fix this. There's some email thread in lore where Abel gave more details and I figured out the issue and we didn't need any more debugging. And then I sent out [1]. Sorry I missed you in the cc lise for [1] -- I try to keep track of everyone to cc but things slip through the cracks sometimes. But at the same time, it's easy to check for emails from me before saying I didn't help or didn't send out fixes :) If you do try to give [1] a shot, there are a bunch of bugs that people pointed out for which I gave fixes on top of [1] in the replies. I was supposed to work on v2 over the holidays, but that didn't happen because of stuff outside my control. > That's ample time to fix this, so I intend to apply this. But I'll > give it a few days for comments. Rob, I'd recommend not applying this because it'll fix it for Dmitry but break someone else's use case. That's the whole reason it takes me a while to send out patches -- it's easy to fix it for a subset of devices, but fixing something without breaking someone else is harder (I still believe it's doable) and it takes a while to test them on all the devices I want to test before sending them out. -Saravana [1] - https://lore.kernel.org/lkml/20220810060040.321697-1-saravanak@xxxxxxxxxx/
