On Wed, 2010-05-26 at 02:16 -0700, David Miller wrote: > From: Eli Cohen <e...@dev.mellanox.co.il> > Date: Wed, 26 May 2010 12:08:52 +0300 > > > So if I understand you correctly, you think that I should not bother > > to set a default value of 1. Each driver that cares about the value > > of this field, will set it however they want. > > I actually mean that the value "0" should mean the first port, > the value "1" should mean the second port, etc.
There's a compatibility problem here though: when user-space looks at this number it can't tell whether "0" really means the first port or that the driver isn't setting dev_id. In order to tell that it would have to check the driver or kernel version too, and this is really nasty (what if the driver was backported?). So I think that 1-based numbering for drivers that previously didn't set dev_id. Why does this matter? I'm maintaining the firmware update program for Solarflare NICs under Linux. Some of the firmware it updates is per-port and some of it is per-board. It needs to be able to tell which net and PCI devices are associated with the same board. At the moment it works on the basis of PCI addresses, but this is unreliable in the presence of virtualisation. It would be better to use board serial number and the port identifier that I just changed the driver to use, but since there are existing driver versions always leave dev_id = 0, I it needs to be able to tell whether dev_id is meaningful. Ben. -- Ben Hutchings, Senior Software Engineer, Solarflare Communications Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked. -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
