On 1/02/2016 23:35, Bjorn Helgaas wrote: --- > > You should be able to tell whether Windows sees the BT878 even without > drivers. I think there might be something in Device Manager, or you > can use a tool like AIDA64 (there was a free trial version last I > checked). I ran up AIDA64. The Hint device was recognised as something slightly different. It also didn't list anything behind the bridge - same issue. Not sure if the Subsystem ID of 0000 is an issue. [ HiNT HB1-SE33 PCI-PCI Bridge ] Device Properties: Device Description HiNT HB1-SE33 PCI-PCI Bridge Bus Type PCI Bus / Device / Function 4 / 1 / 0 Device ID 3388-0021 Subsystem ID 0000-0000 Device Class 0604 (PCI/PCI Bridge) Revision 11 Fast Back-to-Back Transactions Supported, Disabled Device Features: 66 MHz Operation Not Supported Bus Mastering Enabled The IT8893 similarly listed: [ ITE IT8893 PCI Bridge ] Device Properties: Device Description ITE IT8893 PCI Bridge Bus Type PCI Bus / Device / Function 3 / 0 / 0 Device ID 1283-8893 Subsystem ID 0000-0000 Device Class 0604 (PCI/PCI Bridge) Revision 10 Fast Back-to-Back Transactions Not Supported Device Features: 66 MHz Operation Not Supported >> Is there's something needing configuring in that Hint HB6/PCI6140 >> bridge? > > I can't think of anything, but that does seem like the most likely > explanation. > >> When working, it loads the shpchp module, and it does advertise >> itself as "non transparent" mode. > > I see "Hint Corp HB6 Universal PCI-PCI bridge (non-transparent mode)" > in both lspci outputs. Is that what you mean, or do you see a > difference somewhere else? It looks like that string is just looked > up from the device ID; it's not influenced by anything the kernel > does. > >> The other difference is a latency of >> 64 in the working scenario, 32 when not. Not configurable on the AMI >> BIOS unfortunately. > > I did notice the shpchp and latency timer differences, but I couldn't > figure out how they could possibly be related. But it certainly > wouldn't hurt to enable shpchp in your kernel and see if it makes a > difference. > > I can't figure out how the latency timer could be involved either, but > you can try fiddling with it, e.g., set it to 64: > > # setpci -s04:01.0 0x0d.b=0x40 > # echo 1 > /sys/bus/pci/rescan The shpchp module was already in the kernel config, but not used. rmmoding and modprobing again doesn't appear to help. I tried the above setpci and rescan, but that didn't do anything new. Must be a broken BIOS somehow masking the bridge - are we at a dead end? Thanks Richard -- 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
