| Message ID | 20160129162400.GB12965@localhost (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On 29/01/2016 16:24, Bjorn Helgaas wrote: > On Thu, Jan 28, 2016 at 10:23:03AM +0000, Richard F wrote: >> Bjorn, >> >> Thanks for looking at it. Actually I've tried 3 different PCI cards in >> both slots and they all work fine. I have 2 different single channel >> BT878 based PCI cards in there now capturing CCTV 24 x 7, the machine >> stays up for months. That's why it's so odd. Any other pointers? Does >> the kernel need the BIOS to detect the card right? > > The kernel should at least discover the card even if the BIOS doesn't > do anything. But on x86, the BIOS usually *does* configure things, so > it's very possible we could trip over a Linux defect if it doesn't. > > Try booting with "pci=pcie_scan_all". That *shouldn't* make a > difference because this isn't a PCIe device, but maybe our logic is > broken. > > Your topology looks a little strange: > > 00:1c.0 PCIe root port to [bus 01] slot 0 > 00:1c.1 PCIe root port to [bus 02] slot 1 > 00:1c.2 PCIe root port to [bus 03-05] slot 2 > 03:00.0 PCI bridge to [bus 04-05] (Integrated Technology Express) > 04:01.0 PCI bridge to [bus 05] (Hint Corp) > > 00:1c.2 is a normal PCIe Root Port, so the device it's connected to > *should* be a PCIe device, but 03:00.0 doesn't have a PCIe capability. > Is this an adapter card of some kind? It's a motherboard bridge to get from PCIe to legacy PCI slots, quite a few motherboards use it I think. It's not an adapter I plugged in. pci=pcie_scan_all didn't yield anything new, as you expected. I posted the output of DMESG with your patch (in 4.4.0) to the bugzilla https://bugzilla.kernel.org/show_bug.cgi?id=110851 It produced a fair bit of output but doesn't look like the card was recognised. At least modprobe'ing bttv with the right parameters didn't yield the right response. I also tried pci=reouteirq and posted the result, that also didn't help. Please let me know if there's anything else I can try. The AMI BIOS doesn't have any setup parameters for the PCI/e. Thanks Richard > 03:00.0 is an ITE 8893, and we do have a quirk related to a similar > device: > http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/quirks.c?h=v4.4#n3662 > > Can you try the patch below, please? > > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c > index 6d7ab9b..f6d8e85 100644 > --- a/drivers/pci/probe.c > +++ b/drivers/pci/probe.c > @@ -1530,6 +1530,7 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, > if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l)) > return false; > > + dev_info(&bus->dev, "%s %02x %#010x\n", __func__, devfn, *l); > /* some broken boards return 0 or ~0 if a slot is empty: */ > if (*l == 0xffffffff || *l == 0x00000000 || > *l == 0x0000ffff || *l == 0xffff0000) > @@ -1571,6 +1572,7 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn) > struct pci_dev *dev; > u32 l; > > + dev_info(&bus->dev, "%s %02x\n", __func__, devfn); > if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000)) > return NULL; > > @@ -1751,6 +1753,7 @@ struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn) > { > struct pci_dev *dev; > > + dev_info(&bus->dev, "%s %02x\n", __func__, devfn); > dev = pci_get_slot(bus, devfn); > if (dev) { > pci_dev_put(dev); > @@ -1825,6 +1828,7 @@ int pci_scan_slot(struct pci_bus *bus, int devfn) > unsigned fn, nr = 0; > struct pci_dev *dev; > > + dev_info(&bus->dev, "%s %02x\n", __func__, devfn); > if (only_one_child(bus) && (devfn > 0)) > return 0; /* Already scanned the entire slot */ > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sat, Jan 30, 2016 at 05:54:28PM +0000, Richard F wrote: > On 29/01/2016 16:24, Bjorn Helgaas wrote: > > On Thu, Jan 28, 2016 at 10:23:03AM +0000, Richard F wrote: > > Your topology looks a little strange: > > > > 00:1c.0 PCIe root port to [bus 01] slot 0 > > 00:1c.1 PCIe root port to [bus 02] slot 1 > > 00:1c.2 PCIe root port to [bus 03-05] slot 2 > > 03:00.0 PCI bridge to [bus 04-05] (Integrated Technology Express) > > 04:01.0 PCI bridge to [bus 05] (Hint Corp) > > > > 00:1c.2 is a normal PCIe Root Port, so the device it's connected to > > *should* be a PCIe device, but 03:00.0 doesn't have a PCIe capability. > > Is this an adapter card of some kind? > > It's a motherboard bridge to get from PCIe to legacy PCI slots, quite a > few motherboards use it I think. It's not an adapter I plugged in. That makes sense. It sounds like there are two conventional PCI slots? I think it's also a minor platform bug that the 00:1c.2 root port advertises a slot. 1c.2 is connected to a system-integrated device, i.e., 03:00.0, not a slot. This might cause pciehp to claim 1c.2 when it shouldn't. But that's unrelated to the current issue, of course. > I posted the output of DMESG with your patch (in 4.4.0) to the bugzilla > https://bugzilla.kernel.org/show_bug.cgi?id=110851 > > It produced a fair bit of output but doesn't look like the card was > recognised. At least modprobe'ing bttv with the right parameters didn't > yield the right response. I only added printks, so I didn't expect it to change the behavior. I just wanted to confirm that we are scanning the bus and device numbers where we expect the bttv devices to be, and we are. I think your bttv card includes these devices: 04:01.0 PCI-PCI bridge (Hint Corp) 05:0c.0 bt878 05:0c.1 bt878 05:0d.0 bt878 ... 05:0f.1 bt878 For conventional PCI, I think the device number is determined by the slot wiring. That affects the device number of the Hint Corp bridge, so if you move it between slots, it should change from device 01 to something else. The device and function numbers of the bt878 devices are determined by wiring on the card, so those should be the same between machine A and B. These are 5- and 3-bit fields, respectively, so 0c.0 means we have 01100 000 encoded into an 8-bit devfn as 0110 0000 or 0x60. When we tried to read the vendor & device ID from 0c.0, we got no response from the device: pci_bus 0000:05: pci_scan_slot 60 pci_bus 0000:05: pci_scan_single_device 60 pci_bus 0000:05: pci_scan_device 60 pci_bus 0000:05: pci_bus_read_dev_vendor_id 60 0xffffffff I'm out of ideas. Other cards work in this slot; it's only the bttv card that doesn't work. So it seems like it must be something about that card that's different. Maybe somebody on the list will have more ideas? Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Bjorn, Thanks so much for your investigation. Yes, MOBO has 2 PCI slots fed off the IT8893E. This guy - http://linux.derkeiler.com/Mailing-Lists/Debian/2005-08/3243.html had a similar problem 10yrs ago(!), fixed by disabling ACPI, I tried that without any success. I did extract the BIOS tables and disassemble/reassemble them to see if there was anything obvious broken there, and not much shows, a few warnings, AML is pretty indecipherable stuff... I also tried fooling it with some Windows acpi_os_name's matching those in the AML, without luck. For kicks I spun up an old Win XP image today, and it recognised the PCI bridge but may not have been able to see the BT878's behind, but then I didn't have a reliable source for drivers for it. Is there's something needing configuring in that Hint HB6/PCI6140 bridge? When working, it loads the shpchp module, and it does advertise itself as "non transparent" mode. The other difference is a latency of 64 in the working scenario, 32 when not. Not configurable on the AMI BIOS unfortunately. Thanks again Richard On 1/02/2016 19:06, Bjorn Helgaas wrote: > On Sat, Jan 30, 2016 at 05:54:28PM +0000, Richard F wrote: >> On 29/01/2016 16:24, Bjorn Helgaas wrote: >>> On Thu, Jan 28, 2016 at 10:23:03AM +0000, Richard F wrote: >>> Your topology looks a little strange: >>> >>> 00:1c.0 PCIe root port to [bus 01] slot 0 >>> 00:1c.1 PCIe root port to [bus 02] slot 1 >>> 00:1c.2 PCIe root port to [bus 03-05] slot 2 >>> 03:00.0 PCI bridge to [bus 04-05] (Integrated Technology Express) >>> 04:01.0 PCI bridge to [bus 05] (Hint Corp) >>> >>> 00:1c.2 is a normal PCIe Root Port, so the device it's connected to >>> *should* be a PCIe device, but 03:00.0 doesn't have a PCIe capability. >>> Is this an adapter card of some kind? >> >> It's a motherboard bridge to get from PCIe to legacy PCI slots, quite a >> few motherboards use it I think. It's not an adapter I plugged in. > > That makes sense. It sounds like there are two conventional PCI > slots? I think it's also a minor platform bug that the 00:1c.2 root > port advertises a slot. 1c.2 is connected to a system-integrated > device, i.e., 03:00.0, not a slot. This might cause pciehp to claim > 1c.2 when it shouldn't. But that's unrelated to the current issue, of > course. > >> I posted the output of DMESG with your patch (in 4.4.0) to the bugzilla >> https://bugzilla.kernel.org/show_bug.cgi?id=110851 >> >> It produced a fair bit of output but doesn't look like the card was >> recognised. At least modprobe'ing bttv with the right parameters didn't >> yield the right response. > > I only added printks, so I didn't expect it to change the behavior. I > just wanted to confirm that we are scanning the bus and device numbers > where we expect the bttv devices to be, and we are. I think your bttv > card includes these devices: > > 04:01.0 PCI-PCI bridge (Hint Corp) > 05:0c.0 bt878 > 05:0c.1 bt878 > 05:0d.0 bt878 > ... > 05:0f.1 bt878 > > For conventional PCI, I think the device number is determined by the > slot wiring. That affects the device number of the Hint Corp bridge, > so if you move it between slots, it should change from device 01 to > something else. > > The device and function numbers of the bt878 devices are determined by > wiring on the card, so those should be the same between machine A and > B. These are 5- and 3-bit fields, respectively, so 0c.0 means we have > 01100 000 encoded into an 8-bit devfn as 0110 0000 or 0x60. When we > tried to read the vendor & device ID from 0c.0, we got no response > from the device: > > pci_bus 0000:05: pci_scan_slot 60 > pci_bus 0000:05: pci_scan_single_device 60 > pci_bus 0000:05: pci_scan_device 60 > pci_bus 0000:05: pci_bus_read_dev_vendor_id 60 0xffffffff > > I'm out of ideas. Other cards work in this slot; it's only the bttv > card that doesn't work. So it seems like it must be something about > that card that's different. > > Maybe somebody on the list will have more ideas? > > Bjorn > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Feb 01, 2016 at 08:06:51PM +0000, Richard F wrote: > Bjorn, > > Thanks so much for your investigation. > > Yes, MOBO has 2 PCI slots fed off the IT8893E. > This guy - > http://linux.derkeiler.com/Mailing-Lists/Debian/2005-08/3243.html had a > similar problem 10yrs ago(!), fixed by disabling ACPI, I tried that > without any success. Interesting. That makes you think there's some bridge init difference. > I did extract the BIOS tables and > disassemble/reassemble them to see if there was anything obvious broken > there, and not much shows, a few warnings, AML is pretty indecipherable > stuff... I also tried fooling it with some Windows acpi_os_name's > matching those in the AML, without luck. > > For kicks I spun up an old Win XP image today, and it recognised the PCI > bridge but may not have been able to see the BT878's behind, but then I > didn't have a reliable source for drivers for it. 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). > 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 You can also use "lspci -vvv -s04:01.0" and compare with the working system and see if there are other differences. I think AIDA64 will also dump that config space, so you might be able to compare with with what Windows XP does, too. > On 1/02/2016 19:06, Bjorn Helgaas wrote: > > On Sat, Jan 30, 2016 at 05:54:28PM +0000, Richard F wrote: > >> On 29/01/2016 16:24, Bjorn Helgaas wrote: > >>> On Thu, Jan 28, 2016 at 10:23:03AM +0000, Richard F wrote: > >>> Your topology looks a little strange: > >>> > >>> 00:1c.0 PCIe root port to [bus 01] slot 0 > >>> 00:1c.1 PCIe root port to [bus 02] slot 1 > >>> 00:1c.2 PCIe root port to [bus 03-05] slot 2 > >>> 03:00.0 PCI bridge to [bus 04-05] (Integrated Technology Express) > >>> 04:01.0 PCI bridge to [bus 05] (Hint Corp) > >>> > >>> 00:1c.2 is a normal PCIe Root Port, so the device it's connected to > >>> *should* be a PCIe device, but 03:00.0 doesn't have a PCIe capability. > >>> Is this an adapter card of some kind? > >> > >> It's a motherboard bridge to get from PCIe to legacy PCI slots, quite a > >> few motherboards use it I think. It's not an adapter I plugged in. > > > > That makes sense. It sounds like there are two conventional PCI > > slots? I think it's also a minor platform bug that the 00:1c.2 root > > port advertises a slot. 1c.2 is connected to a system-integrated > > device, i.e., 03:00.0, not a slot. This might cause pciehp to claim > > 1c.2 when it shouldn't. But that's unrelated to the current issue, of > > course. > > > >> I posted the output of DMESG with your patch (in 4.4.0) to the bugzilla > >> https://bugzilla.kernel.org/show_bug.cgi?id=110851 > >> > >> It produced a fair bit of output but doesn't look like the card was > >> recognised. At least modprobe'ing bttv with the right parameters didn't > >> yield the right response. > > > > I only added printks, so I didn't expect it to change the behavior. I > > just wanted to confirm that we are scanning the bus and device numbers > > where we expect the bttv devices to be, and we are. I think your bttv > > card includes these devices: > > > > 04:01.0 PCI-PCI bridge (Hint Corp) > > 05:0c.0 bt878 > > 05:0c.1 bt878 > > 05:0d.0 bt878 > > ... > > 05:0f.1 bt878 > > > > For conventional PCI, I think the device number is determined by the > > slot wiring. That affects the device number of the Hint Corp bridge, > > so if you move it between slots, it should change from device 01 to > > something else. > > > > The device and function numbers of the bt878 devices are determined by > > wiring on the card, so those should be the same between machine A and > > B. These are 5- and 3-bit fields, respectively, so 0c.0 means we have > > 01100 000 encoded into an 8-bit devfn as 0110 0000 or 0x60. When we > > tried to read the vendor & device ID from 0c.0, we got no response > > from the device: > > > > pci_bus 0000:05: pci_scan_slot 60 > > pci_bus 0000:05: pci_scan_single_device 60 > > pci_bus 0000:05: pci_scan_device 60 > > pci_bus 0000:05: pci_bus_read_dev_vendor_id 60 0xffffffff > > > > I'm out of ideas. Other cards work in this slot; it's only the bttv > > card that doesn't work. So it seems like it must be something about > > that card that's different. > > > > Maybe somebody on the list will have more ideas? > > > > Bjorn > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-pci" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Wed, Feb 03, 2016 at 01:52:42PM +0000, Richard F wrote: > 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. I don't think the Subsystem ID is relevant. > [ 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? I mentioned "lspci -vvv" before, but I meant "lspci -xxx": that will show you the whole config space. You could compare them between the working and non-working machines. I think the Hint bridge is the important device. The BIOS isn't directly involved when we're enumerating devices. It may have done setup earlier that affects how the hardware works, but it doesn't have a chance to intervene when we do config reads to find devices. So if the BIOS configured something in the bridge that causes this problem, the "lspci -xxx" should show it. Other than that, I don't have any other ideas. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 6d7ab9b..f6d8e85 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -1530,6 +1530,7 @@ bool pci_bus_read_dev_vendor_id(struct pci_bus *bus, int devfn, u32 *l, if (pci_bus_read_config_dword(bus, devfn, PCI_VENDOR_ID, l)) return false; + dev_info(&bus->dev, "%s %02x %#010x\n", __func__, devfn, *l); /* some broken boards return 0 or ~0 if a slot is empty: */ if (*l == 0xffffffff || *l == 0x00000000 || *l == 0x0000ffff || *l == 0xffff0000) @@ -1571,6 +1572,7 @@ static struct pci_dev *pci_scan_device(struct pci_bus *bus, int devfn) struct pci_dev *dev; u32 l; + dev_info(&bus->dev, "%s %02x\n", __func__, devfn); if (!pci_bus_read_dev_vendor_id(bus, devfn, &l, 60*1000)) return NULL; @@ -1751,6 +1753,7 @@ struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn) { struct pci_dev *dev; + dev_info(&bus->dev, "%s %02x\n", __func__, devfn); dev = pci_get_slot(bus, devfn); if (dev) { pci_dev_put(dev); @@ -1825,6 +1828,7 @@ int pci_scan_slot(struct pci_bus *bus, int devfn) unsigned fn, nr = 0; struct pci_dev *dev; + dev_info(&bus->dev, "%s %02x\n", __func__, devfn); if (only_one_child(bus) && (devfn > 0)) return 0; /* Already scanned the entire slot */