Re: [PATCH v5] PCI: dwc: Wait for link up only if link is started

[Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>]

On Mon, Jan 29, 2024 at 12:21:51PM +0530, Ajay Agarwal wrote:
> On Sat, Jan 20, 2024 at 08:04:34PM +0530, Manivannan Sadhasivam wrote:
> > On Fri, Jan 19, 2024 at 11:29:22PM +0530, Ajay Agarwal wrote:
> > > On Fri, Jan 19, 2024 at 01:22:19PM +0530, Manivannan Sadhasivam wrote:
> > > > On Fri, Jan 12, 2024 at 03:00:06PM +0530, Ajay Agarwal wrote:
> > > > > In dw_pcie_host_init() regardless of whether the link has been
> > > > > started or not, the code waits for the link to come up. Even in
> > > > > cases where start_link() is not defined the code ends up spinning
> > > > > in a loop for 1 second. Since in some systems dw_pcie_host_init()
> > > > > gets called during probe, this one second loop for each pcie
> > > > > interface instance ends up extending the boot time.
> > > > > 
> > > > 
> > > > Which platform you are working on? Is that upstreamed? You should mention the
> > > > specific platform where you are observing the issue.
> > > >
> > > This is for the Pixel phone platform. The platform driver for the same
> > > is not upstreamed yet. It is in the process.
> > > 
> > 
> > Then you should submit this patch at the time of the driver submission. Right
> > now, you are trying to fix a problem which is not present in upstream. One can
> > argue that it is a problem for designware-plat driver, but honestly I do not
> > know how it works.
> > 
> > - Mani
> >
> Yes Mani, this can be a problem for the designware-plat driver. To me,
> the problem of a second being wasted in the probe path seems pretty
> obvious. We will wait for the link to be up even though we are not
> starting the link training. Can this patch be accepted considering the
> problem in the dw-plat driver then?
> 

If that's the case with your driver, when are you starting the link training?

> Additionally, I have made this patch a part of a series [1] to keep the
> functional and refactoring changes separate. Please let me know if you
> see a concern with that.
> 

I have responded to this series with my concerns.

- Mani

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