On Thu, 2015-09-10 at 12:55 -0700, zubin kumar wrote: > hi, > > i had some queries regarding pcie behavior in fedora16 vs fedora20. > > observation on fedora16 - > when i connect a pcie device in slot#3 with fedora16, the pcie device > comes up properly. i am able to see the pcie device ID, class code and > all the memory bars. > > observation on fedora20 - > however when i connect the same device to a fedora20 system, the > machine itself does not boot. and the motherboard keeps sending out > the fundamental reset. then it keeps looping in a reset-bootup > sequence. > > fedora16 kernel - 3.6.11 fc16 x86x64 arch > fedora20 kernel - 3.11.10-4 fc20 x86x64 arch > > queries - > 1) i was wondering if pcie enumeration is effected by OS or is it > controlled directly by motherboard and OS settings/kernel etc. dont > impact PCIe enum at all? > 2) what could be the differences between fedora16 Vs fedora20 that > could cause the pc to boot properly in fedora16 but go into a > reset-boot loop in fedora20? > 3) any log file i can check to see what might be causing the issue on the host? > 4) my pcie device enumerates as an memory device. could this impact > the fedora16 / fedora20 differently? > > additional observation - > i have tried other pcie slots on both fedora16 and fedora20 machines. > either machines are not able to even detect the pcie device if i use > any slot other than slot#3. i checked the BIOS settings and all the > pcie slots are enabled. > > if anyone can give some insight into what could be causing the > difference in behavior in pcie enum in fedora16 vs fedora20, that > would be great. > > thanks in advance ... Hi Zubin, The problem description seems to already presume that the fault is at the kernel, but it's not even clear to me from the description whether the F16 vs F20 tests are different kernels on different systems or different kernels on the same system. If these are different systems, an obvious test would be to try F16 on the system with the reset-boot loop issue. When you see a reset-boot loop, does it occur during BIOS initialization or after the kernel has started booting? If the latter, can you capture any of the kernel log via serial console? The fact that the card isn't even visible in other slots in the "working" system certainly raises concerns whether the card is actually a generic PCIe device or somehow specific to that platform. Obviously knowing the card and something about the system is potentially useful, otherwise slot#3 doesn't mean much. Thanks, Alex -- 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
