[linux-usb-devel] 2.4.20 ehci-hcd not loading due to ehci_reset

[Richard CHAN Shih-Ping]

Hi David and list,

I have an Intel EHCI controller where ehci-hcd doesn't load due
to handshake() failure in ehci_reset(). System is 2.4.20. This used
to work with RedHat 2.4.18-18.8.0 kernel with a very old ehci-hcd.c
that doesn't check the return value from ehci_reset().

00:1d.0 USB Controller: Intel Corp. 82801DB USB (Hub #1) (rev 01)
00:1d.1 USB Controller: Intel Corp. 82801DB USB (Hub #2) (rev 01)
00:1d.2 USB Controller: Intel Corp. 82801DB USB (Hub #3) (rev 01)
00:1d.7 USB Controller: Intel Corp. 82801DB USB EHCI Controller (rev 01)

dmesg:
PCI: Found IRQ 10 for device 00:1d.7
PCI: Setting latency timer of device 00:1d.7 to 64
hcd.c: ehci-hcd @ 00:1d.7, Intel Corp. 82801DB USB EHCI Controller
hcd.c: irq 10, pci mem e0ae7c00
usb.c: new USB bus registered, assigned bus number 4
hcd.c: remove: 00:1d.7, state 0
usb.c: USB bus 4 deregistered

I have tracked the problem to ehci_start() calling ehci_reset() calling handshake():

static int ehci_reset (struct ehci_hcd *ehci)
{
....
....
return handshake (&ehci->regs->command, CMD_RESET, 0, 250);
}

handshake() is always returning non-zero due to ETIMEOUT, I've also tried
increasing 250 to 2000; if I ignore the return code from ehci_reset()
the driver loads.

PCI: Found IRQ 10 for device 00:1d.7
PCI: Setting latency timer of device 00:1d.7 to 64
hcd.c: ehci-hcd @ 00:1d.7, Intel Corp. 82801DB USB EHCI Controller
hcd.c: irq 10, pci mem e0ae7c00
usb.c: new USB bus registered, assigned bus number 4
ehci-hcd.c: ehci_start called
ehci-hcd.c: enabled 64bit PCI DMA (DAC)
ehci-hcd.c: USB 2.0 support enabled, EHCI rev 1.00, ehci-hcd 2002-Sep-23
hub.c: USB hub found
hub.c: 6 ports detected

If I change the handshake line (copied from the handshake() line in ehci_halt()) to
return handshake (&ehci->regs->command, CMD_RESET, CMD_RESET, 250);

then the driver loads. Since I'm not sure of the meaning of either of these two kludges
what do you folks think?

Cheers
Richard

lspci -v
00:1d.7 USB Controller: Intel Corp. 82801DB USB EHCI Controller (rev 01) (prog-if 20 [EHCI])
Subsystem: Micro-star International Co Ltd: Unknown device 3981
Flags: bus master, medium devsel, latency 0, IRQ 10
Memory at dffffc00 (32-bit, non-prefetchable) [size=1K]
Capabilities: [50] Power Management version 2
Capabilities: [58] #0a [2080]













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