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Groups > linux.kernel > #1627665 > unrolled thread
| Started by | Haiyang Zhang <haiyangz@exchange.microsoft.com> |
|---|---|
| First post | 2017-04-20 18:40 +0200 |
| Last post | 2017-04-20 20:40 +0200 |
| Articles | 4 — 4 participants |
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[PATCH] pci-hyperv: Use only 16 bit integer for PCI domain Haiyang Zhang <haiyangz@exchange.microsoft.com> - 2017-04-20 18:40 +0200
RE: [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain Haiyang Zhang <haiyangz@microsoft.com> - 2017-04-20 20:40 +0200
Re: [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain Christoph Hellwig <hch@infradead.org> - 2017-04-20 21:20 +0200
Re: [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain Bjorn Helgaas <bhelgaas@google.com> - 2017-04-20 20:40 +0200
| From | Haiyang Zhang <haiyangz@exchange.microsoft.com> |
|---|---|
| Date | 2017-04-20 18:40 +0200 |
| Subject | [PATCH] pci-hyperv: Use only 16 bit integer for PCI domain |
| Message-ID | <tynhE-2OS-19@gated-at.bofh.it> |
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. Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> --- drivers/pci/host/pci-hyperv.c | 4 +++- 1 files changed, 3 insertions(+), 1 deletions(-) diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c index e73880c..b18dff3 100644 --- a/drivers/pci/host/pci-hyperv.c +++ b/drivers/pci/host/pci-hyperv.c @@ -1334,9 +1334,11 @@ static void put_pcichild(struct hv_pci_dev *hpdev, * can have shorter names than based on the bus instance UUID. * Only the first device serial number is used for domain, so the * domain number will not change after the first device is added. + * The lower 16 bits of the serial number is used, otherwise some + * drivers may not be able to handle it. */ if (list_empty(&hbus->children)) - hbus->sysdata.domain = desc->ser; + hbus->sysdata.domain = desc->ser & 0xFFFF; list_add_tail(&hpdev->list_entry, &hbus->children); spin_unlock_irqrestore(&hbus->device_list_lock, flags); return hpdev; -- 1.7.1
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| From | Haiyang Zhang <haiyangz@microsoft.com> |
|---|---|
| Date | 2017-04-20 20:40 +0200 |
| Message-ID | <typ9L-3Yq-7@gated-at.bofh.it> |
| In reply to | #1627665 |
> -----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
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| From | Christoph Hellwig <hch@infradead.org> |
|---|---|
| Date | 2017-04-20 21:20 +0200 |
| Message-ID | <typMu-4rW-19@gated-at.bofh.it> |
| In reply to | #1627736 |
On Thu, Apr 20, 2017 at 06:37:35PM +0000, Haiyang Zhang wrote: > It's Nvidia driver. Which of the many nvidia drivers in the tree? Just fix it instead of coming up with stupid workarounds like this.
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| From | Bjorn Helgaas <bhelgaas@google.com> |
|---|---|
| Date | 2017-04-20 20:40 +0200 |
| Message-ID | <typ9L-3Yq-9@gated-at.bofh.it> |
| In reply to | #1627665 |
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). > Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com> > --- > drivers/pci/host/pci-hyperv.c | 4 +++- > 1 files changed, 3 insertions(+), 1 deletions(-) > > diff --git a/drivers/pci/host/pci-hyperv.c b/drivers/pci/host/pci-hyperv.c > index e73880c..b18dff3 100644 > --- a/drivers/pci/host/pci-hyperv.c > +++ b/drivers/pci/host/pci-hyperv.c > @@ -1334,9 +1334,11 @@ static void put_pcichild(struct hv_pci_dev *hpdev, > * can have shorter names than based on the bus instance UUID. > * Only the first device serial number is used for domain, so the > * domain number will not change after the first device is added. > + * The lower 16 bits of the serial number is used, otherwise some > + * drivers may not be able to handle it. > */ > if (list_empty(&hbus->children)) > - hbus->sysdata.domain = desc->ser; > + hbus->sysdata.domain = desc->ser & 0xFFFF; > list_add_tail(&hpdev->list_entry, &hbus->children); > spin_unlock_irqrestore(&hbus->device_list_lock, flags); > return hpdev; > -- > 1.7.1 >
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