On Wed, Jun 25, 2014 at 10:49 PM, Shawn Guo <shawn.guo@xxxxxxxxxxxxx> wrote: > On Thu, Jun 26, 2014 at 12:43:19AM -0300, Fabio Estevam wrote: >> On Thu, Jun 26, 2014 at 12:12 AM, Shawn Guo <shawn.guo@xxxxxxxxxxxxx> wrote: >> > On Tue, Jun 24, 2014 at 04:18:27PM -0300, Fabio Estevam wrote: >> >> From: Fabio Estevam <fabio.estevam@xxxxxxxxxxxxx> >> >> >> >> When the mx6 PCI conctroller is initialized in the bootloader we see a kernel >> >> hang inside imx6_add_pcie_port(). >> >> >> >> Adding a 30ms delay allows the kernel to boot. >> > >> > We may not want to add a random delay into the driver before we >> > understand the root cause of the issue. >> >> Yes, that's why I sent this as RFC and also explained it below the --- >> line that I am actually trying to get some help with this issue. >> >> > >> > Do you see this issue with FSL kernel? >> >> Yes, it also hangs. >> >> It is reproducible in 100% of the boots. Just need to use mainline >> U-boot (which has PCI driver enabled by default). >> I am using an Intel Wifi 7260 PCI card. This was also reported by >> other folks in the U-boot list. > > Richard, > > Can you schedule some time to look at this issue? I think it will come > to us sooner or later if any our customer enables PCIe before launching > kernel? > > Shawn > Shawn / Richard, I am also affected by this issue on IMX6 boards that I support. If I enable PCI in the bootloader I see similar hangs. I have the following hardware configurations on my bench: 1. IMX6DL + i210 (same PCI setup as Fabio's above, but DL instead of Q) 2. IMX6Q + ath9k device 3. IMX6DL + PLX PEX860x PCIe-to-PCIe bridge with various devices behind the bridge, using a clock buffer from IMX6 PCIe clock 4. IMX6Q + PLX PEX860x PCIe-to-PCIe bridge with various devices behind the bridge, using a clock buffer from IMX6 PCIe clock 5. IMX6Q + PLX PEX860x PCIe-to-PCIe bridge with various devices behind the bridge using a clock generator (always on, ignoring the PCIe clock) For all of the above I have no PCI issues using 3.14/3.15/3.16-rc2/vendor 3.10.17_1.0.0_ga unless I enable PCI in the bootloader. When I do so, all of the above configurations hang somewhere around PCI init/enumeration. The same occurs with the most recent vendor kernel 3.10.17_1.0.0_ga kernel (works when PCI is disabled in the bootloader, hangs otherwise). When I apply Fabio's patch above to the 3.16-rc2 kernel I find that scenarios #4 and #5 above then work, #3 boots but the PLX bridge fails all config cycles (0xff's), #2 boots but with no PCIe link, and #1 above still hangs. Previously, when I have dug into this particular 'hang' issue on 3.15 I found that the delay needed to be between imx6_pcie_probe() requesting and asserting reset_gpio low, and before setting IOMUX_GPR1:18 to power down the PCIe PHY (note here, that the PHY is currently enabled in the bootloader when PCI is enabled there). When I apply Fabio's patch above to the most recent vendor kernel 3.10.17_1.0.0_ga I still hang in all cases. So while I agree there is something horribly wrong with IMX6 PCI still, I don't think Fabio's patch is the right solution and I don't have anything better at this point in time. I'm happy to share any hardware with anyone that can work through this issue. Thanks, Tim -- 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
