Messages in this thread | | | From | Saravana Kannan <> | Date | Wed, 27 Jul 2022 17:10:57 -0700 | Subject | Re: [PATCH v6] amba: Remove deferred device addition |
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On Wed, Jul 27, 2022 at 3:16 PM Russell King (Oracle) <linux@armlinux.org.uk> wrote: > > On Wed, Jul 27, 2022 at 11:19:35AM -0700, Saravana Kannan wrote: > > The uevents generated for an amba device need PID and CID information > > that's available only when the amba device is powered on, clocked and > > out of reset. So, if those resources aren't available, the information > > can't be read to generate the uevents. To workaround this requirement, > > if the resources weren't available, the device addition was deferred and > > retried periodically. > > > > However, this deferred addition retry isn't based on resources becoming > > available. Instead, it's retried every 5 seconds and causes arbitrary > > probe delays for amba devices and their consumers. > > > > Also, maintaining a separate deferred-probe like mechanism is > > maintenance headache. > > > > With this commit, instead of deferring the device addition, we simply > > defer the generation of uevents for the device and probing of the device > > (because drivers needs PID and CID to match) until the PID and CID > > information can be read. This allows us to delete all the amba specific > > deferring code and also avoid the arbitrary probing delays. > > Oh, this is absolutely horrible. I can apply it cleanly to my "misc" > branch, but it then conflicts when I re-merge my tree for the for-next > thing (which is only supposed to be for sfr - the hint is in the name!) > for-next is basically my "fixes" plus "misc" branch and anything else I > want sfr to pick up for the -next tree.
Btw, this is the repo I was using because I couldn't find any amba repo. git://git.armlinux.org.uk/~rmk/linux-arm.git
Is the misc branch visible somewhere because I don't see it in that repo? Or is that just a local branch? Also, what does sfr stand for (s* for next)?
In case this helps, all the conflicts are due to this commit: 8030aa3ce12e ARM: 9207/1: amba: fix refcount underflow if amba_device_add() fails
It's fixing bugs in code I'm deleting. So if you revert that, I can give you a patch that'll apply across 5.18 and 5.19.
Let me know if you want me to do that.
> Applying this has to be on top of that merge commit, otherwise the > conflicts are horrid, but that then means I need to send Linus the > for-next merge commit (which I don't normally do.) > > Gah, we have too many changes to drivers/bus/amba.c in this cycle, > some of them which have been submitted for 5.19 as fixes (and thus > are not in 5.18-rc1 which the misc branch is based upon for other > patch dependency reasons) and others in the misc branch for the next > cycle - and now your patch wants both, which I can't do without > rebasing the misc branch. > > Sadly, getting these changes into GregKH's tree will just create a > conflict between Greg's tree and my tree. > > Can we postpone this please?
I guess? It's not like I can force either of you :) Or maybe you can ask Greg to pick it up after he picks up your for-next?
Anyway, whatever option can get this pulled in reasonably soon is fine by me -- I can send out v7 on whatever tree you want. I've been nursing this patch for a year and I want to get it in before I hit more conflicts/issues and give up on it :)
-Saravana
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