On Tue, May 18, 2010 at 05:24:53PM -0500, Praveen Kalamegham wrote: > Greg KH wrote: >> On Tue, May 18, 2010 at 11:49:55AM -0500, Praveen Kalamegham wrote: >>> Why is this check needed? >>> >> Because the PCI hotplug spec says that this is the "rule". No PCI >> hotplugging is allowed for video devices due to the wierd BIOS issues >> involved in setting up a large number of video devices. >> > Thanks for the quick reply. I looked through the PCI spec (3.0), PCI > Hotplug spec (1.1), or PCIe spec (2.1) but could not find any reference to > this rule. Could you point me in the right direction? It used to be in the PCI Hotplug spec, but note that the last time I read that, was back in 2001 or so. I could go dig through the PCI Hotplug spec again if you really can't find it. > And to be clear, > I'm only talking about PCIe hotplug, not PCI (probably not relevant to the > BIOS issue you referred to but mentioning just to be sure). There is no difference here, PCIe video cards work the same was as PCI video cards at the BIOS and OS level, right? They can still have POST requirements from what I recall. > Since these are computational GPU devices, I wouldn't think they would > suffer from the same BIOS issues but not knowing the specifics, I'm > merely guessing. Yes, they might not, but then again, they might, it all depends on the video card itself. Which was why the spec said that VGA-like devices could not be hotplugged, and hence, we try to check that in the kernel code. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
