On 5/13/2014 9:20 PM, Felipe Balbi wrote:
Hi,
On Thu, May 08, 2014 at 03:03:07PM +0530, George Cherian wrote:
Enabling the core interrupts in complete is too late for XHCI, and stops
xhci from proper operation. So remove prepare and complete and disable/enable
isn't this a bug in xhci ? I mean the driver should make no assumption
as to when IRQs are enabled, why do we need to enable IRQs earlier when
the device is only considered "ready for use" after ->complete()
finishes executing ?
I dont think its a bug in xhci. In case of xhci-pci driver it actually
does an
hcd->driver->pci_suspend (xhci_suspend) followed by synchronize_irq()
and the does a pci_disable_device(). In resume path it calls
pci_enable_device()
followed by hcd->driver->pci_resume(xhci_resume).
In case of dwc3-omap we do have a wrapper register which can still
disable the XHCI IRQs
even though the xhci driver enables the interrupts internally.
Now dwc3-omap wrapper driver should not actually fiddle with the core
Interrupt
enable/disable except in probe/remove.
From documentation we have:
107 * @complete: Undo the changes made by @prepare(). This method is executed for
108 * all kinds of resume transitions, following one of the resume callbacks:
109 * @resume(), @thaw(), @restore(). Also called if the state transition
110 * fails before the driver's suspend callback: @suspend(), @freeze() or
111 * @poweroff(), can be executed (e.g. if the suspend callback fails for one
112 * of the other devices that the PM core has unsuccessfully attempted to
113 * suspend earlier).
114 * The PM core executes subsystem-level @complete() after it has executed
115 * the appropriate resume callbacks for all devices.
which tells me that using ->complete() to reenable IRQs is ok here.
Specially when you consider that the role of ->prepare() is to prevent
new children from being created and, for a USB host, that means we
should prevent hub port changes.
Probably the patch should have been to still keep the complete/prepare
in place
but not disable the core interrupts, rather enable/disable only the
wrapper interrupt.
cheers
--
-George
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