On 28.11.2018 13:19, Stefan Agner wrote: > On 21.11.2018 14:47, Leonard Crestez wrote: >> On 11/20/2018 11:28 PM, Trent Piepho wrote: >>> On Tue, 2018-11-20 at 21:42 +0100, Stefan Agner wrote: >>>> On 20.11.2018 20:13, Trent Piepho wrote: >> >>>>> It also seems to me that this doesn't need to be in the internal pci >>>>> config access functions. The driver shouldn't be reading registers >>>>> that don't exist anyway. It's really about trying to fix sysfs access >>>>> to registers that don't exist. So maybe it should be done there. >>>> >>>> That was my first approach, see: >>> >>> Yes, but that just used the pci device id which applies to every IMX >>> design. >>> >>> It's also not totally correct, as it seems real registers after 0x200 >>> do work on imx6, and that would prevent access to them. >> >> I see that Lorenzo already accepted the patch in pci/dwc: >> >> https://git.kernel.org/pub/scm/linux/kernel/git/lpieralisi/pci.git/commit/?h=pci/dwc&id=f14eaec153aaebbe940ddd21e4198cc2abc927c2 >> >> My tests show that this series breaks pci cards on 6qdl and I think it >> should be reverted until a fix is found. Are you OK with this? >> >> Fixing might require an entirely different approach. > > I tried to reproduce this issue on Apalis iMX6 (i.MX 6Q) with a ath9k > PCIe WiFi card, the issue you are seeing did not happen. My lspci looks > as follows: > > root@ea210c63d739:/# lspci -v > 00:00.0 PCI bridge: Synopsys, Inc. Device abcd (rev 01) (prog-if 00 > [Normal decode]) > Flags: bus master, fast devsel, latency 0, IRQ 255 > Memory at 01000000 (32-bit, non-prefetchable) [size=1M] > Bus: primary=00, secondary=01, subordinate=ff, sec-latency=0 > Memory behind bridge: 01100000-011fffff > [virtual] Expansion ROM at 01200000 [disabled] [size=64K] > Capabilities: [40] Power Management version 3 > Capabilities: [50] MSI: Enable- Count=1/1 Maskable+ 64bit+ > Capabilities: [70] Express Root Port (Slot-), MSI 00 > Capabilities: [100] Advanced Error Reporting > Capabilities: [140] Virtual Channel > lspci: Unable to load libkmod resources: error -12 > > 01:00.0 Network controller: Qualcomm Atheros AR928X Wireless Network > Adapter (PCI-Express) (rev 01) > Subsystem: Foxconn International, Inc. Device e007 > Flags: bus master, fast devsel, latency 0, IRQ 312 > Memory at 01100000 (64-bit, non-prefetchable) [size=64K] > Capabilities: [40] Power Management version 2 > Capabilities: [50] MSI: Enable- Count=1/1 Maskable- 64bit- > Capabilities: [60] Express Legacy Endpoint, MSI 00 > Capabilities: [90] MSI-X: Enable- Count=1 Masked- > Capabilities: [100] Advanced Error Reporting > Capabilities: [140] Virtual Channel > Capabilities: [160] Device Serial Number 00-00-00-00-00-00-00-00 > Kernel driver in use: ath9k > > > I did also setup a WiFi network and transmitted some packages, but I did > not get a nobody carred message. Do you have an idea why that might be? > > # cat /proc/interrupts > ... > 312: 10967 0 0 0 GPC 123 Level > ath9k > ... > > > Your conclusion in this thread seem reasonable, hence reverting the > issue does. However, I still would like to reproduce the issue so I can > make sure that future patches don't break it :-) Hm, I realized that I need to enable CONFIG_PCIEPORTBUS and set ath9k.use_msi=1 to get MSI for that card. However, it seems that ath9k does not behave well in that setup. It does get interrupts, and seems to work to some degree, but I was not successful in transmitting data over WiFi, but that might be an entirly different thing. However, what I noticed is that when CONFIG_PCIEPORTBUS and CONFIG_PCI_MSI is enabled, MSI works but legacy interrupt seem not to fire anymore. That is true for ath9k as well as e1000e (using e1000e.IntMode=0 to force legacy). Is that a known issue/limitation with i.MX 6 PCIe? -- Stefan
