Re: [Xen-devel] RE: [Question] Do we need to support devices that do not strictly follow the PCI-e specification?

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

Will do.

 K.


On 9/10/08 10:31, "Shan, Haitao" <haitao.shan@xxxxxxxxx> wrote:

Hi, Keir,
 
There is already a fix for calculating the size of PCI-e capability properly. The changeset is 77fba269. But this changeset is not in xen-3.3-testing. Can you help to check in that changeset to xen-3.3-testing tree?
Thanks!
 
Shan Haitao
 

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From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Shan, Haitao
Sent: 2008年10月9日 17:08
To: Keir Fraser; xen-devel@xxxxxxxxxxxxxxxxxxx
Cc: Huang, Zhiteng; Tian, Kevin; Jiang, Yunhong; Li, Xin B
Subject: [Xen-devel] RE: [Question] Do we need to support devices that do not strictly follow the PCI-e specification?

Oh, I made some mistakes. I have just checked PCI-e 1.1 spec. It seems the definition of this capability structure is different with PCI-e 2.0. I will check more and find a solution.
 

---

From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
Sent: 2008年10月9日 17:03
To: Shan, Haitao; xen-devel@xxxxxxxxxxxxxxxxxxx
Cc: Jiang, Yunhong; Li, Xin B; Tian, Kevin; Huang, Zhiteng
Subject: Re: [Question] Do we need to support devices that do not strictly follow the PCI-e specification?




On 9/10/08 09:28, "Shan, Haitao" <haitao.shan@xxxxxxxxx> wrote:
Hi, Keir,
 
When debugging recently, I found some devices that did not follow the PCI-e specification strictly. Below is an example.

From PCI-e spec, PCI-e capability occupies 0x3c bytes of configuration space. Unimplemented registers are reserved and hardwired to zero. But for device listed below, PCI-e capability should begin at 0x4C and end at 0x88. But this device implements MSI, VPD, MSI-X capabilities in the reserved spaces. Current code can not handle this.

My question is do we need to add hacks to handle such kinds of devices?
I thought PCI capability offsets could be dynamically determined? If so, or there are other means to easily determine actual capability offsets without requiring explicit device-quirk lists, we should employ those means.

 -- Keir

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