Re: [linux-usb-devel] Re: OHCI problems with suspend/resume

From: Pavel Machek (pavel_at_ucw.cz)
Date: 07/26/03

  • Next message: Pavel Machek: "Re: swsusp updates" 
    Date:	Sat, 26 Jul 2003 23:01:24 +0200
To: David Brownell <david-b@pacbell.net>

    Hi!

    > >>I'm not sure how the design is intended to work, but either way something
    > >>needs to be fixed.
    >
    > Yes, it seems like all the HCDs (and the hub driver) need attention.

    Why the hub driver?

    For basic functionality, you simply power it down (doing virtual
    unplug), and power it back up on resume (doing virtual plug of all
    devices). That should work reasonably for everything but mass-storage.

    > Plus, the enumeration process should respect hubs' power budgets,
    > and handle overcurrent better. I had a hub re-enumerate over forty
    > times not that long ago, just because it enabled too many things at
    > once and the surge currents made lots of trouble. Plenty of power,
    > if it got turned on carefully enough... :)

    Havin enough juice in "common case", but not in "worst case" is not
    too legal situation, is it?

    > >Could well be. I need to spend some time auditing power management
    > >in the USB drivers in general. The idea here is that a sub-driver
    > >(USB device driver) should make sure it has no more pending URBs
    > >when returning from suspend() and the HCD driver should just cancel
    > >pending URBs if still any and reject any one that would be submited
    >
    > Agreed, this needs work. Some USB device drivers will likely need to
    > implement suspend()/resume() callbacks, which thoughtfully enough the
    > driver model conversion already gave us. At one point it was planned
    > to have it automatically traverse the devices and suspend, leaves up to
    > root; and resume in the reverse order. Is that behaving now?

    Yes.

    > Suspend should likely enable remote wakeup (trevor.pering@intel.com
    > has been asking about that), at least as a config option. That'll
    > be useful for things like keyboards and mice.

    Okay, but we need normal suspend/resume working first :-).

                                                                    Pavel 

    -- 
When do you have a heart between your knees?
[Johanka's followup: and *two* hearts?]
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/
  • Next message: Pavel Machek: "Re: swsusp updates"

    Relevant Pages

    • Re: Nvidia MCP55 Machine reboots on ixgb driver load
      ... There are some serious hardware compatibility issues with the ixgb mixing it with other cards on the same PCI-X bus, ... loading the driver with debug does not appear to produce ... 02:00.0 PCI bridge: NEC Corporation uPD720400 PCI Express - PCI/PCI-X Bridge ... ACPI: Power Button ...
      (Linux-Kernel)
    • Re: KB835732 breaks S3 standby timer
      ... APM is a BIOS ... for power control. ... most late SCSI and NDIS drivers hook WDM ACPI messages. ... Windows driver interaction issues, you should disable ACPI for these ...
      (microsoft.public.win2000.windows_update)
    • Re: [linux-pm] Power Management framework proposal
      ... if they are why should this new API need to worry about that? ... clocks seems like it fits well into the model) becouse some power modes ... the onenand driver needs to adjust its timing parameters ... the software needs to know what the interconnects and dependancies ...
      (Linux-Kernel)
    • Re: Power Management framework proposal
      ... A power policy management framework doesn't need a unified framework (I ... I can see that if things really are different then it's worth doing different things to control them. ... to have any ability to control the mode of anything at runtime requires that the code doing so must have specific knowledge of the driver in question. ... 50 35 quarter power to the backlight ...
      (Linux-Kernel)
    • Re: i wanna look cute today...
      ... London buses are still as reliable as ever, ... power line for the pick-up to reach, ... Mostly only happened if the driver took a wrong turn onto a road with no ... female cyclists interviewed seemed to have similar ...
      (uk.people.support.depression)