[alsa-devel] What can change after suspend ?

Robert Hancock hancockrwd at gmail.com
Wed Oct 28 00:41:27 CET 2009

On Tue, Oct 27, 2009 at 5:17 PM, Giuliano Pochini <pochini at shiny.it> wrote:
> I'm adding suspend/resume support to echoaudio drivers. I was
> reading /Documentation/power/pci.txt:
> "
>        pci_set_power_state(PCI_D0);
>        pci_restore_state();
>        /* device's irq possibly is changed, driver should take care */
> "
> The card does not support D[0-3] states. The driver suspends the card by
> turning the DSP off, without changing the PCI state. Can IRQ, memory mapped
> regions, whatever, change on resume ?
> Are pci_save_state() and pci_enable_wake() useful/required in this case ?

I don't think an audio card would have need for pci_enable_wake, but
pci_save_state and pci_restore_state are mandatory, otherwise PCI
configuration space won't get restored after resume.

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