ohci1394 problem (MMIO broken) (was 2.6.25-rc6-git6: Reported regressions from 2.6.24)

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

Rafael J. Wysocki wrote:
> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=10080
> Subject		: 2.6.25-rc2: ohci1394 problem (MMIO broken)
> Submitter	: Thomas Meyer <thomas@m3y3r.de>
> Date		: 2008-02-20 08:47 (31 days old)
> References	: http://lkml.org/lkml/2008/2/20/58
> Handled-By	: Stefan Richter <stefanr@s5r6.in-berlin.de>

This bug is alas an orphan.  It is /not/ handled by me, because it is 
not an IEEE 1394 subsystem bug and I have no idea what to do about it.

Note the following:

   - Several or all of ohci1394's MMIO reads return ~0 (all bits set
     to one) --- or 0 --- where different values are expected.

   - In http://lkml.org/lkml/2008/2/23/244 we get to see a
     WARNING: at arch/x86/mm/ioremap.c:137 __ioremap+0xa7/0x16a()
     which is "WARN_ON_ONCE(page_is_ram(pfn));".
     After that, the failures start.
     But before that, "Unknown symbol" messages pop up when ohci1394
     is loaded.  These symbols are implemented by ieee1394 on which
     ohci1394 depends.

More context from http://lkml.org/lkml/2008/2/23/244:

> [  199.908169] ath_pci: wifi0: Atheros 5424/2424: mem=0x94300000, irq=17

ath_hal taints the kernel.

> [  847.318678] ohci1394: Unknown symbol hpsb_iso_wake
> [  847.318791] ohci1394: Unknown symbol hpsb_resume_host
...

Some unexplained build problem.

> [  856.789954] ACPI: PCI Interrupt 0000:0c:03.0[A] -> GSI 19 (level, 
> low) -> IRQ 19
> [  856.790040] ------------[ cut here ]------------
> [  856.790044] WARNING: at arch/x86/mm/ioremap.c:137 __ioremap+0xa7/0x16a()
> [  856.790048] Modules linked in: ohci1394(+) ieee1394 wlan_wep 
> wlan_scan_sta ath_rate_sample ath_pci wlan ath_hal(P) firmware_class 
> fuse snd_seq snd_seq_device nls_iso8859_15 nls_cp850 vfat fat usbhid 
> appletouch applesmc input_polldev led_class dummy binfmt_misc tun 
> pktcdvd loop msr cpuid coretemp hwmon eeprom cpufreq_powersave 
> cpufreq_conservative acpi_cpufreq thermal ehci_hcd tpm_infineon i2c_i801 
> i2c_core tpm uhci_hcd usbcore tpm_bios processor ac battery sr_mod 
> rng_core iTCO_wdt button firewire_ohci firewire_core sg snd_hda_intel 
> snd_pcm snd_timer snd soundcore snd_page_alloc evdev intel_agp cdrom 
> [last unloaded: microcode]
> [  856.790119] Pid: 7140, comm: insmod Tainted: P         2.6.25-rc2 #115
> [  856.790125]  [<c011e5ab>] warn_on_slowpath+0x40/0x4f
> [  856.790143]  [<c0118045>] __wake_up+0x29/0x39
> [  856.790154]  [<c0277305>] netlink_broadcast+0x26e/0x2af
> [  856.790169]  [<c01cc36b>] kobject_uevent_env+0x33d/0x361
> [  856.790178]  [<c025ef2b>] pci_mmcfg_write+0xc4/0xd5
> [  856.790187]  [<c0260157>] raw_pci_write+0x3e/0x46
> [  856.790200]  [<c01148f8>] __ioremap+0xa7/0x16a
> [  856.790210]  [<f8b14425>] ohci1394_pci_probe+0x20c/0x5a6 [ohci1394]
> [  856.790226]  [<c01d63f1>] pci_device_probe+0x36/0x55
> [  856.790236]  [<c02226cb>] driver_probe_device+0x9d/0x114
...
> [  856.790598] ---[ end trace 5b0384c17c339107 ]---
> [  856.943807] ohci1394: fw-host0: Get PHY Reg timeout 
> [0x00008400/0x00000000/100]

MMIO read expected 0x00008400, got 0x00000000.

...
> [  921.826439] ohci1394: fw-host0: Unhandled interrupt(s) 0xfc7cfe0c

MMIO read got random bits in the interrupt event register.

...
> [  994.471724] ohci1394: fw-host0: OHCI-1394 0.35 (PCI): IRQ=[19]  
> MMIO=[100000000-1000007ff]  Max Packet=[65536]  IR/IT contexts=[32/32]

The values for Max Packet and IR/IT contexts came from bogus MMIO reads.

Thomas, you wrote in http://lkml.org/lkml/2008/3/17/316 that the problem 
resurfaced.
   - Are the "Unknown symbol"s still there?  These are not supposed to
     happen.
   - Is the "WARNING: at arch/x86/mm/ioremap.c" still there?
   - Can you reproduce it without the atheros driver?

Rafael, no matter how it looks, this is not "handled-by: me". :-)
I don't know nothing about kbuild nor about arch/x86/mm nor about WLAN.
The IEEE 1394 bits in the bug of which I know something about are purely 
accidental.
-- 
Stefan Richter
-=====-==--- --== =-==-
http://arcgraph.de/sr/