On Thu, Aug 15, 2013 at 05:45:42PM +0100, Peter Maydell wrote: > 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: > Do you mean my patch fixes the traceback below as a side effect ? Would be great ... it would be one more reason to get it applied.
> 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 > Does it get better if you apply Arnd's patch ? > 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.) > Might make sense, but I think it should be a separate patch. If I understand correctly, my patch fixes the SCSI problem. Is that correct ? If so, can we get it applied to mainline ? Thanks, Guenter
