Re: [PATCH v3] bus: mhi: Add inbound buffers allocation flag

[Bjorn Andersson <bjorn.andersson@linaro.org>]

On Thu 24 Jun 17:45 CDT 2021, Loic Poulain wrote:

> Hi Bjorn,
> 
> On Thu, 24 Jun 2021 at 22:30, Bjorn Andersson
> <bjorn.andersson@linaro.org> wrote:
> >
> > On Thu 24 Jun 15:28 CDT 2021, Loic Poulain wrote:
> >
> > > Currently, the MHI controller driver defines which channels should
> > > have their inbound buffers allocated and queued. But ideally, this is
> > > something that should be decided by the MHI device driver instead,
> > > which actually deals with that buffers.
> > >
> > > Add a flag parameter to mhi_prepare_for_transfer allowing to specify
> > > if buffers have to be allocated and queued by the MHI stack.
> > >
> > > Keep auto_queue flag for now, but should be removed at some point.
> > >
> > > Signed-off-by: Loic Poulain <loic.poulain@linaro.org>
> > > Tested-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
> > > Reviewed-by: Bhaumik Bhatt <bbhatt@codeaurora.org>
> > > Reviewed-by: Hemant Kumar <hemantk@codeaurora.org>
> > > Reviewed-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> > > Acked-by: Jakub Kicinski <kuba@kernel.org>
> > > Link: https://lore.kernel.org/r/1621603519-16773-1-git-send-email-loic.poulain@linaro.org
> > > Signed-off-by: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
> >
> > What's the intention with this patch? Why is Mani the last S-o-b when
> > you're the one sending it and why is it sent only to linux-arm-msm@?
> 
> Actually the previous version of that patch has already been applied
> to mhi-next, but has been nacked as part of Mani's PR, so it's a quick
> follow-up fix to address the issue.
> 

Thanks, that makes sense.

> > And completely separate of the practical matters, is it true that qrtr
> > is the only client that use this pre-allocation feature?
> 
> yes.
> 

Then I think we should fix qrtr instead.

> > Would it be a net gain to simplify the core and add buffer allocation to qrtr instead?
> 
> Yes, I 100% agree, but I however would prefer to keep that for a
> follow-up series since this patch fixes a real issue for MHI/PCI
> modems (no inbound QRTR buffers allocated).
> 

I certainly don't mind this patch going upstream while we put such
refactoring in the backlog.

Thanks,
Bjorn