Re: [PATCH v18 08/20] PCI: dwc: Add dw_pcie_link_set_max_link_width()

[Bjorn Helgaas <helgaas@kernel.org>]

On Tue, Aug 08, 2023 at 03:15:33AM +0300, Serge Semin wrote:
> On Mon, Aug 07, 2023 at 06:40:34PM -0500, Bjorn Helgaas wrote:
> > On Tue, Aug 08, 2023 at 01:53:11AM +0300, Serge Semin wrote:
> > > On Tue, Aug 01, 2023 at 01:50:59AM +0000, Yoshihiro Shimoda wrote:
> > > > > From: Serge Semin, Sent: Tuesday, August 1, 2023 8:54 AM
> > > > > On Fri, Jul 21, 2023 at 04:44:40PM +0900, Yoshihiro Shimoda wrote:
> > > > > > To improve code readability, add dw_pcie_link_set_max_link_width().
> > > > > > ...
> > 
> > > > > > @@ -1009,49 +1049,5 @@ void dw_pcie_setup(struct dw_pcie *pci)
> > > > > >  	val |= PORT_LINK_DLL_LINK_EN;
> > > > > >  	dw_pcie_writel_dbi(pci, PCIE_PORT_LINK_CONTROL, val);
> > > > > >
> > > > > > -	if (!pci->num_lanes) {
> > > > > > -		dev_dbg(pci->dev, "Using h/w default number of lanes\n");
> > > > > > -		return;
> > > > > > -	}
> > > > > > -
> > > > > > -	/* Set the number of lanes */
> > > > > 
> > > > > > -	val &= ~PORT_LINK_FAST_LINK_MODE;
> > > > > 
> > > > > My series contains the patch which drops this line:
> > > > <snip URL>
> > > > > So either pick my patch up and add it to your series or still pick it up
> > > > > but with changing the authorship and adding me under the Suggested-by
> > > > > tag with the email-address I am using to review your series. Bjorn,
> > > > > what approach would you prefer? Perhaps alternative?
> 
> > I don't really see the argument here.  AFAICT, Yoshihiro's patch
> > (https://lore.kernel.org/r/20230721074452.65545-9-yoshihiro.shimoda.uh@renesas.com)
> > is a trivial refactoring to make dw_pcie_link_set_max_link_width(),
> > which might be reused elsewhere later, which seems perfectly fine.
> > 
> > It'd be fine with me to add a little detail in the commit log to
> > reference the Synopsys manual, which I don't have.  But doesn't seem
> > like a big deal to me.
> 
> More details are in one of my earlier comments to this patch which
> Yoshihiro promised to add to the patch log on the next patchset
> revision. You can read it here:
> https://lore.kernel.org/linux-pci/20230721074452.65545-1-yoshihiro.shimoda.uh@renesas.com/T/#m8ac364249f40c726da88316b67f11a6d55068ef0
> 
> > Dropping the PORT_LINK_FAST_LINK_MODE mask seems like a separate
> > question that should be in a separate patch.
> > https://lore.kernel.org/linux-pci/20230611192005.25636-6-Sergey.Semin@baikalelectronics.ru/
> > says it's redundant, so it sounds more like a cleanup than a fix.
> 
> That's the point of my comment. There is no need in copying that mask
> to the dw_pcie_link_set_max_link_width() method because first it's
> unrelated to the link-width setting, second it's redundant. There is
> my patch dropping the mask with the proper justification:
> https://lore.kernel.org/linux-pci/20230611192005.25636-6-Sergey.Semin@baikalelectronics.ru/
> It would be good to either merge it in before the Yoshihiro' series or
> add my patch to the Yoshihiro' patchset. But it's in the patchwork
> limbo now, neither you nor Lorenzo or Krzysztof were willing to merge
> it in. That's why I suggested to move the patch here with the denoted
> alterations. Could you give your resolution whether the suggested
> movement is ok or perhaps you or Lorenzo or Krzysztof consider merge
> it in as is?

If I understand Yoshihiro's patch, it pulls code out into
dw_pcie_link_set_max_link_width() without changing that code.  That
seems like the best approach to me because it's very easy to review.

If we want to remove a little redundant code later in a separate
patch, that's fine too but doesn't seem urgent.  I don't think they
need to be tied together.

Bjorn