From: "Cui, Dexuan" <dexuan.cui@intel.com>
To: Bjorn Helgaas <bhelgaas@google.com>
Cc: Jiang Liu <liuj97@gmail.com>, Don Dutile <ddutile@redhat.com>,
Yinghai Lu <yinghai@kernel.org>,
Taku Izumi <izumi.taku@jp.fujitsu.com>,
"Rafael J . Wysocki" <rjw@sisk.pl>,
Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>,
Yijing Wang <wangyijing@huawei.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>
Subject: RE: [PATCH v3 00/32] provide interfaces to access PCIe capabilities registers
Date: Thu, 23 Aug 2012 01:00:40 +0000 [thread overview]
Message-ID: <A25F549E4D43CD42B4C02DF47A1913230FE53087@SHSMSX102.ccr.corp.intel.com> (raw)
In-Reply-To: <CAErSpo5ftvKLF2=1ixzp1KroNLKh_s-b5hi9aFv3X7PpqisGwg@mail.gmail.com>
Bjorn Helgaas wrote on 2012-08-23:
> On Mon, Aug 20, 2012 at 9:40 PM, Cui, Dexuan <dexuan.cui@intel.com>
> wrote:
>> Bjorn Helgaas wrote on 2012-08-21:
>
>>> I am still concerned about reset_intel_82599_sfp_virtfn(). It looks
>>> wrong and possibly unnecessary. It looks wrong because it sets
>>> PCI_EXP_DEVCTL_BCR_FLR and blindly clears all other bits in
>>> PCI_EXP_DEVCTL. Most of the bits are probably cleared by the FLR
>>> anyway, but Aux Power PM Enable is RWS ("sticky"), so it is *not*
>>> modified by FLR. Therefore, using reset_intel_82599_sfp_virtfn() has
>>> the probably unintended side effect of clearing Aux Power PM Enable.
>>>
>>> It looks possibly unnecessary because the generic pcie_flr() does
>>> essentially the same thing, so it's not clear why we need a special
>>> case for 82599.
>
>> I think reset_intel_82599_sfp_virtfn() is correct AND necessary.
>> (pcie_flr() doesn't work here)
>>
>> Please note the 82599 VF is a special PCIe device that doesn't report
>> PCIe FLR capability though actually it does support that.
>> That is why we put it in quirks.c. :-)
>>
>> The PCI_EXP_DEVCTL_AUX_PME bit of the 82599 VF is read-only and
>> always zero.
>>
>> Please see
>>
> http://www.intel.com/content/dam/doc/datasheet/82599-10-gbe-controller-
> datasheet.pdf
>> 9.5 Virtual Functions Configuration Space
>> Table 9.7 VF PCIe Configuration Space
>> 9.5.2.2.1 VF Device Control Register (0xA8; RW)
>
> Thanks, Dexuan!
>
> The 82599 does report FLR in the DEVCAP for the PF (sec 9.3.10.4), but
> not in the DEVCAP for the VF (sec 9.5), which indeed means we can't
> use pcie_flr() on the VFs. I wonder whether this error appears in any
> other devices.
>
> The VF DEVCTL register (sec 9.5.2.2.1) is RO and zero except for
> "Initiate FLR" unlike the PF DEVCTL (sec 9.3.10.5). The
> read/modify/write done by pcie_flr() would work on the VF but is not
> necessary.
>
> The VF DEVSTA register (sec 9.5.2.2.2) does have an active
> "Transaction Pending" bit. That suggests to me that we should wait
> for it to be clear, as pcie_flr() does.
I agree.
>
> What would you think of a patch like the following? My idea is to
> make it the same as pcie_flr() except for the absolutely necessary
> differences. With this patch, the only difference is that we don't
> look at the 82599 DEVCAP FLR bit.
Hi Bjorn,
Thanks for the patch!
It seems good to me (BTW, I don't have such a device at
hand to test)
Thanks,
-- Dexuan
next prev parent reply other threads:[~2012-08-23 1:00 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-01 15:54 [PATCH v3 00/32] provide interfaces to access PCIe capabilities registers Jiang Liu
2012-08-01 15:54 ` [PATCH v3 01/32] PCI: add pcie_flags_reg into struct pci_dev to cache PCIe capabilities register Jiang Liu
2012-08-01 15:54 ` [PATCH v3 02/32] PCI: introduce pci_pcie_type(dev) to replace pci_dev->pcie_type Jiang Liu
2012-08-01 15:54 ` [PATCH v3 03/32] PCI: remove unused field pcie_type from struct pci_dev Jiang Liu
2012-08-01 15:54 ` [PATCH v3 04/32] PCI: add PCIe capabilities access functions to hide differences among PCIe specs Jiang Liu
2012-08-01 15:54 ` [PATCH v3 05/32] PCI/core: use PCIe capabilities access functions to simplify implementation Jiang Liu
2012-08-01 15:54 ` [PATCH v3 06/32] PCI/hotplug: " Jiang Liu
2012-08-02 1:30 ` Kaneshige, Kenji
2012-08-01 15:54 ` [PATCH v3 07/32] PCI/portdrv: " Jiang Liu
2012-08-02 1:33 ` Kaneshige, Kenji
2012-08-01 15:54 ` [PATCH v3 08/32] PCI/pciehp: " Jiang Liu
2012-08-02 1:37 ` Kaneshige, Kenji
2012-08-01 15:54 ` [PATCH v3 09/32] PCI/PME: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 10/32] PCI/AER: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 11/32] PCI/ASPM: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 12/32] PCI/ARM: " Jiang Liu
2012-08-01 17:20 ` Stephen Warren
2012-08-02 5:58 ` Thierry Reding
2012-08-03 18:05 ` Stephen Warren
2012-08-01 15:54 ` [PATCH v3 13/32] PCI/MIPS: " Jiang Liu
2012-08-13 21:40 ` David Daney
2012-08-01 15:54 ` [PATCH v3 14/32] PCI/tile: " Jiang Liu
2012-08-01 21:07 ` Chris Metcalf
2012-08-01 15:54 ` [PATCH v3 15/32] PCI/r8169: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 16/32] PCI/broadcom: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 17/32] PCI/igb: " Jiang Liu
2012-08-02 22:12 ` Jeff Kirsher
2012-08-01 15:54 ` [PATCH v3 18/32] PCI/vxge: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 19/32] PCI/mlx4: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 20/32] PCI/niu: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 21/32] PCI/myri10ge: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 22/32] PCI/chelsio: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 23/32] PCI/atl1c: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 24/32] PCI/ath9k: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 25/32] PCI/iwl: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 26/32] PCI/mthca: " Jiang Liu
2012-08-02 21:46 ` Roland Dreier
2012-08-01 15:54 ` [PATCH v3 27/32] PCI/qib: " Jiang Liu
2012-08-01 17:30 ` Marciniszyn, Mike
2012-08-01 15:54 ` [PATCH v3 28/32] PCI/qla: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 29/32] PCI/radeon: " Jiang Liu
2012-08-01 16:04 ` Deucher, Alexander
2012-08-01 15:54 ` [PATCH v3 30/32] PCI/tsi721: " Jiang Liu
2012-08-09 14:16 ` Bounine, Alexandre
2012-08-01 15:54 ` [PATCH v3 31/32] PCI/et131x: " Jiang Liu
2012-08-01 15:54 ` [PATCH v3 32/32] PCI/rtl8192e: " Jiang Liu
2012-08-14 4:25 ` [PATCH v3 00/32] provide interfaces to access PCIe capabilities registers Bjorn Helgaas
2012-08-14 15:46 ` Jiang Liu
2012-08-20 15:26 ` Jiang Liu
2012-08-20 15:35 ` Bjorn Helgaas
2012-08-20 15:47 ` Jiang Liu
2012-08-20 16:10 ` Bjorn Helgaas
2012-08-20 22:13 ` Bjorn Helgaas
2012-08-21 4:40 ` Cui, Dexuan
2012-08-22 16:28 ` Bjorn Helgaas
2012-08-23 1:00 ` Cui, Dexuan [this message]
2012-08-23 1:51 ` Don Dutile
2012-08-21 15:59 ` Jiang Liu
2012-08-22 17:08 ` Bjorn Helgaas
2012-08-24 18:52 ` Bjorn Helgaas
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