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From: Stuart Hayes <stuart.w.hayes@gmail.com>
To: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	Austin Bolen <austin_bolen@dell.com>,
	Keith Busch <keith.busch@intel.com>,
	Alexandru Gagniuc <mr.nuke.me@gmail.com>,
	"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	"Gustavo A . R . Silva" <gustavo@embeddedor.com>,
	Sinan Kaya <okaya@kernel.org>,
	Oza Pawandeep <poza@codeaurora.org>,
	linux-pci@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Lukas Wunner <lukas@wunner.de>
Subject: Re: [PATCH 2/3] PCI: pciehp: Wait for PDS if in-band presence is disabled
Date: Thu, 10 Oct 2019 15:37:28 -0500
Message-ID: <CAL5oW02uRk-ZLMaE6Skt7rX6xy=sQNttfSZ2N1JRBXPfjJpZNg@mail.gmail.com> (raw)
In-Reply-To: <CAHp75VfNjnAxua6ESx1Vp=57O=pVM10P1UK8bGNQUk7FeY=Dmw@mail.gmail.com>

On Thu, Oct 10, 2019 at 12:40 AM Andy Shevchenko
<andy.shevchenko@gmail.com> wrote:
>
> On Thu, Oct 10, 2019 at 8:37 AM Andy Shevchenko
> <andy.shevchenko@gmail.com> wrote:
> > On Wed, Oct 9, 2019 at 11:05 PM Stuart Hayes <stuart.w.hayes@gmail.com> wrote:
>
> > > +static void pcie_wait_for_presence(struct pci_dev *pdev)
> > > +{
> > > +       int timeout = 1250;
>
> > > +       bool pds;
>
> Also this is redundant. Just use the following outside the loop
>
>  if (!retries)
>    pc_info(...);
>
> .
>
> > > +       u16 slot_status;
> > > +
> > > +       while (true) {
> > > +               pcie_capability_read_word(pdev, PCI_EXP_SLTSTA, &slot_status);
> > > +               pds = !!(slot_status & PCI_EXP_SLTSTA_PDS);
> > > +               if (pds || timeout <= 0)
> > > +                       break;
> > > +               msleep(10);
> > > +               timeout -= 10;
> > > +       }
> >
> > Can we avoid infinite loops? They are hard to parse (in most cases,
> > and especially when it's a timeout loop)
> >
> > unsigned int retries = 125; // 1250 ms
> >
> > do {
> >  ...
> > } while (--retries);
> >
> > > +
> > > +       if (!pds)
> > > +               pci_info(pdev, "Presence Detect state not set in 1250 msec\n");
> > > +}
> >
> > --
> > With Best Regards,
> > Andy Shevchenko
>
>
>
> --
> With Best Regards,
> Andy Shevchenko

Thank you for the feedback!  An infinite loop is used several other places in
this driver--this keeps the style similar.  I can change it as you suggest,
though, if that would be preferable to consistency.

  reply index

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-09 20:05 [PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link Stuart Hayes
2019-10-09 20:05 ` [PATCH 1/3] PCI: pciehp: Add support for disabling in-band presence Stuart Hayes
2019-10-09 20:05 ` [PATCH 2/3] PCI: pciehp: Wait for PDS if in-band presence is disabled Stuart Hayes
2019-10-10  5:37   ` Andy Shevchenko
2019-10-10  5:40     ` Andy Shevchenko
2019-10-10 20:37       ` Stuart Hayes [this message]
2019-10-11  6:49         ` Andy Shevchenko
2019-10-11  8:48           ` Andy Shevchenko
2019-10-11  9:05             ` Andy Shevchenko
2019-10-09 20:05 ` [PATCH 3/3] PCI: pciehp: Add dmi table for in-band presence disabled Stuart Hayes
  -- strict thread matches above, loose matches on Subject: below --
2019-10-01 21:14 [PATCH 0/3] PCI: pciehp: Do not turn off slot if presence comes up after link Stuart Hayes
2019-10-01 21:14 ` [PATCH 2/3] PCI: pciehp: Wait for PDS if in-band presence is disabled Stuart Hayes

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