From: Haiyang Zhang <haiyangz@microsoft.com>
To: Bjorn Helgaas <bhelgaas@google.com>,
        Piotr Jaroszynski <pjaroszynski@nvidia.com>
CC: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
        KY Srinivasan <kys@microsoft.com>,
        Stephen Hemminger <sthemmin@microsoft.com>,
        "olaf@aepfle.de" <olaf@aepfle.de>,
        "vkuznets@redhat.com" <vkuznets@redhat.com>,
        "driverdev-devel@linuxdriverproject.org" 
        <driverdev-devel@linuxdriverproject.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain
Thread-Topic: [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain
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Date: Thu, 20 Apr 2017 18:37:35 +0000
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> -----Original Message-----
> From: Bjorn Helgaas [mailto:bhelgaas@google.com]
> Sent: Thursday, April 20, 2017 2:33 PM
> To: Haiyang Zhang <haiyangz@microsoft.com>
> Cc: linux-pci@vger.kernel.org; KY Srinivasan <kys@microsoft.com>;
> Stephen Hemminger <sthemmin@microsoft.com>; olaf@aepfle.de;
> vkuznets@redhat.com; driverdev-devel@linuxdriverproject.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain
> 
> On Thu, Apr 20, 2017 at 11:35 AM, Haiyang Zhang
> <haiyangz@exchange.microsoft.com> wrote:
> > From: Haiyang Zhang <haiyangz@microsoft.com>
> >
> > This patch uses the lower 16 bits of the serial number as PCI
> > domain, otherwise some drivers may not be able to handle it.
> 
> Can you give any more details about this?  Which drivers, for
> instance?  Why do drivers care about the domain at all?  Can we or
> should we make this more explicit and consistent in the PCI core,
> e.g., pci_domain_nr() is currently defined to return "int"; maybe it
> should be u32?  (Although I think "int" is the same size as "u32" on
> all arches anyway).

It's Nvidia driver.

Piotr, could you explain why the driver expects 16 bit domain number?

Thanks,
- Haiyang