On 13 August 2013 04:40, Guenter Roeck <li...@roeck-us.net> wrote: > Patch tested and working with qemu 1.5.2, using the configuration file > from the yocto project. Patch applied on top of kernel version 3.11-rc5.
OK, I tested this on PB926+PCI backplane hardware, and it is definitely better than current mainline, in that the test USB card that I have no longer causes the kernel to generate this sort of backtrace: ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver ehci-pci: EHCI PCI platform driver ehci-pci 0000:00:1e.2: EHCI Host Controller ehci-pci 0000:00:1e.2: new USB bus registered, assigned bus number 1 ehci-pci 0000:00:1e.2: irq 91, io mem 0x50002000 ehci-pci 0000:00:1e.2: USB 2.0 started, EHCI 1.00 usb usb1: New USB device found, idVendor=1d6b, idProduct=0002 usb usb1: New USB device strings: Mfr=3, Product=2, SerialNumber=1 usb usb1: Product: EHCI Host Controller usb usb1: Manufacturer: Linux 3.10.0+ ehci_hcd usb usb1: SerialNumber: 0000:00:1e.2 hub 1-0:1.0: USB hub found hub 1-0:1.0: 3 ports detected ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver ohci-pci: OHCI PCI platform driver ohci-pci 0000:00:1e.0: OHCI PCI host controller ohci-pci 0000:00:1e.0: new USB bus registered, assigned bus number 2 irq 93: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 1 Comm: swapper Not tainted 3.10.0+ #9 [<c00187d4>] (unwind_backtrace+0x0/0xf0) from [<c0015b48>] (show_stack+0x10/0x14) [<c0015b48>] (show_stack+0x10/0x14) from [<c0054cac>] (__report_bad_irq+0x24/0xb8) [<c0054cac>] (__report_bad_irq+0x24/0xb8) from [<c005511c>] (note_interrupt+0x1cc/0x230) [<c005511c>] (note_interrupt+0x1cc/0x230) from [<c005363c>] (handle_irq_event_percpu+0xac/0x1c4) [<c005363c>] (handle_irq_event_percpu+0xac/0x1c4) from [<c005377c>] (handle_irq_event+0x28/0x38) [<c005377c>] (handle_irq_event+0x28/0x38) from [<c00558c8>] (handle_level_irq+0x80/0xd4) [<c00558c8>] (handle_level_irq+0x80/0xd4) from [<c0052fb4>] (generic_handle_irq+0x2c/0x40) [<c0052fb4>] (generic_handle_irq+0x2c/0x40) from [<c016bf38>] (fpga_irq_handle+0x3c/0x50) [<c016bf38>] (fpga_irq_handle+0x3c/0x50) from [<c0052fb4>] (generic_handle_irq+0x2c/0x40) [<c0052fb4>] (generic_handle_irq+0x2c/0x40) from [<c0013e8c>] (handle_IRQ+0x30/0x84) [<c0013e8c>] (handle_IRQ+0x30/0x84) from [<c0008750>] (vic_handle_irq+0x5c/0x9c) [<c0008750>] (vic_handle_irq+0x5c/0x9c) from [<c00165c0>] (__irq_svc+0x40/0x4c) Exception stack(0xc7829cc8 to 0xc7829d10) 9cc0: 00000001 0000000a 00000100 20000013 00000002 00000024 9ce0: c7828000 c0476980 3fb96c1c c0443950 c04693c0 00000001 c0456a50 c7829d10 9d00: c0025f38 c0025fa8 20000013 ffffffff [<c00165c0>] (__irq_svc+0x40/0x4c) from [<c0025fa8>] (__do_softirq+0x80/0x1b4) [<c0025fa8>] (__do_softirq+0x80/0x1b4) from [<c00263a4>] (irq_exit+0x54/0x90) [<c00263a4>] (irq_exit+0x54/0x90) from [<c0013e90>] (handle_IRQ+0x34/0x84) [<c0013e90>] (handle_IRQ+0x34/0x84) from [<c0008750>] (vic_handle_irq+0x5c/0x9c) [<c0008750>] (vic_handle_irq+0x5c/0x9c) from [<c00165c0>] (__irq_svc+0x40/0x4c) Exception stack(0xc7829d80 to 0xc7829dc8) 9d80: 00000000 0000005d 20000000 00000000 c79bb7e0 c0446990 60000013 c79c0000 9da0: 0000005d 00000000 c04469c4 00000001 00000000 c7829dc8 c00555c8 c0054460 9dc0: 40000013 ffffffff [<c00165c0>] (__irq_svc+0x40/0x4c) from [<c0054460>] (__setup_irq+0x1f4/0x3f0) [<c0054460>] (__setup_irq+0x1f4/0x3f0) from [<c00548ac>] (request_threaded_irq+0xb4/0x138) [<c00548ac>] (request_threaded_irq+0xb4/0x138) from [<c01fa7a8>] (usb_add_hcd+0x4f0/0x6f0) [<c01fa7a8>] (usb_add_hcd+0x4f0/0x6f0) from [<c0206bdc>] (usb_hcd_pci_probe+0x200/0x36c) [<c0206bdc>] (usb_hcd_pci_probe+0x200/0x36c) from [<c017467c>] (pci_device_probe+0x68/0x90) [<c017467c>] (pci_device_probe+0x68/0x90) from [<c01b3a80>] (driver_probe_device+0x78/0x200) [<c01b3a80>] (driver_probe_device+0x78/0x200) from [<c01b3c94>] (__driver_attach+0x8c/0x90) [<c01b3c94>] (__driver_attach+0x8c/0x90) from [<c01b2288>] (bus_for_each_dev+0x58/0x88) [<c01b2288>] (bus_for_each_dev+0x58/0x88) from [<c01b29e8>] (bus_add_driver+0xd8/0x220) [<c01b29e8>] (bus_add_driver+0xd8/0x220) from [<c01b4258>] (driver_register+0x78/0x144) [<c01b4258>] (driver_register+0x78/0x144) from [<c0410820>] (do_one_initcall+0x94/0x154) [<c0410820>] (do_one_initcall+0x94/0x154) from [<c04109cc>] (kernel_init_freeable+0xec/0x1b0) [<c04109cc>] (kernel_init_freeable+0xec/0x1b0) from [<c0323104>] (kernel_init+0x8/0xe4) [<c0323104>] (kernel_init+0x8/0xe4) from [<c00130b0>] (ret_from_fork+0x14/0x24) handlers: [<c01f7e48>] usb_hcd_irq Disabling IRQ #93 However it still doesn't seem to reliably detect the USB harddisk plugged into the card, so I think there may be further issues, possibly some subset of those Arnd identified and fixed with this patch: http://permalink.gmane.org/gmane.linux.ports.arm.kernel/93397 so I'd like to continue testing. The other thing this patch should (IMHO) have is the line in pci_versatile_setup() which tells QEMU that the kernel really does expect hardware-like behaviour: --- a/arch/arm/mach-versatile/pci.c +++ b/arch/arm/mach-versatile/pci.c @@ -295,6 +295,19 @@ int __init pci_versatile_setup(int nr, struct pci_sys_data *sys) __raw_writel(PHYS_OFFSET, local_pci_cfg_base + PCI_BASE_ADDRESS_2); /* + * For many years the kernel and QEMU were symbiotically buggy + * in that they both assumed the same broken IRQ mapping. + * QEMU therefore attempts to auto-detect old broken kernels + * so that they still work on newer QEMU as they did on old + * QEMU. Since we now use the correct (ie matching-hardware) + * IRQ mapping we write a definitely different value to a + * PCI_INTERRUPT_LINE register to tell QEMU that we expect + * real hardware behaviour and it need not be backwards + * compatible for us. This write is harmless on real hardware. + */ + __raw_writel(0, VERSATILE_PCI_VIRT_BASE+PCI_INTERRUPT_LINE); + + /* * Do not to map Versatile FPGA PCI device into memory space */ pci_slot_ignore |= (1 << myslot); I appreciate that QEMU-specific code in the kernel is a bit ugly, but (a) 99.9% of the people running this code are going to be running it on QEMU (b) the bugs in this area have been extremely long-standing in both the kernel and QEMU and so there are a lot of legacy kernel images out there that worked just fine with QEMU (c) it's rather less code than I have in QEMU as the QEMU-side part of this backwards-compatibility autodetection. (Without this line QEMU will guess whether the kernel is broken or not and will get it right most but not necessarily all of the time.) thanks -- PMM
