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Subject[PATCH] Make e100 suspend handler support PCI cards lacking PM capability
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,
causing a S2R request to immediately get back up to the desktop,
losing network access in the process (rtnl mutex deadlock).

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;
+
if (wake) {
return pci_prepare_to_sleep(pdev);
} else {

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