lkml.org 
[lkml]   [2009]   [Jun]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH] Make e100 suspend handler support PCI cards lacking PM capability
    Date
    On Saturday 13 June 2009, Andreas Mohr wrote:
    > Hi all,
    >
    > after having added non-MII PHY card support to e100, I noticed that
    > the suspend handler rejects power-management non-capable PCI cards,

    Well, that means we have a bug somewhere in the PCI PM core.

    > causing a S2R request to immediately get back up to the desktop,
    > losing network access in the process (rtnl mutex deadlock).

    That's bad.

    >
    > ChangeLog:
    > Support PCI cards which are lacking power management capability
    > in the e100 suspend handler.
    >
    >
    > Frankly I was unsure how to best add this to the driver in a clean way.
    > Usually drivers use pci_set_power_state(..., pci_choose_state(...))
    > in order to avoid the rejection of an open-coded
    > pci_set_power_state(..., PCI_D3hot) in case of a non-PM card,
    > however pci_choose_state() depends on the _pm-internal_ pm_message_t type,
    > which was doable in .suspend directly but not at the other e100
    > driver locations where it was used.
    >
    > Next attempt was to extend __e100_power_off() with a pci_power_t parameter,
    > however since __e100_power_off() is called by two locations,
    > that meant that I'd have to use pci_choose_state() at _both_ call sites.
    >
    > Thus I simply resorted to do a brute-force yet most simple
    > pci_find_capability() check in the __e100_power_off() function.
    >
    >
    > Tested on 2.6.30-rc8 and suspending/resuming fine, checkpatch.pl:ed.
    > Patch against 2.6.30-rc8 with my original non-MII support patch applied.
    > (should apply fine in any case, I'd think).
    > Intended for testing in -mmotm or so.
    >
    > Thanks!
    >
    > Signed-off-by: Andreas Mohr <andi@lisas.de>
    >
    >
    > --- linux-2.6.30-rc8.e100/drivers/net/e100.c.my_patch_orig 2009-06-13 18:47:53.000000000 +0200
    > +++ linux-2.6.30-rc8.e100/drivers/net/e100.c 2009-06-13 20:27:46.000000000 +0200
    > @@ -2897,6 +2897,13 @@ static void __e100_shutdown(struct pci_d
    >
    > static int __e100_power_off(struct pci_dev *pdev, bool wake)
    > {
    > + /* some older devices don't support PCI PM
    > + * (e.g. mac_82557_D100_B combo card with 80c24 PHY)
    > + * - skip those! (they most likely won't support WoL either)
    > + */
    > + if (!pci_find_capability(pdev, PCI_CAP_ID_PM))
    > + return 0;

    Devices without PCI_CAP_ID_PM may still be power-manageable by ACPI, so
    returning 0 at this point is not a general solution.

    > +
    > if (wake) {
    > return pci_prepare_to_sleep(pdev);

    pci_prepare_to_sleep() is supposed to return 0 for your device. I'll have a
    look at it.

    Best,
    Rafael


    \
     
     \ /
      Last update: 2009-06-14 00:31    [W:0.026 / U:3.060 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site