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SubjectRe: [PATCH 2/2] USB: ehci-platform: Support ehci reset after resume quirk
On Mon, 22 Dec 2014, Wu Liang feng wrote:

> The EHCI controller doesn't properly detect the case when

"The" EHCI controller? I don't know what EHCI controller you're
talking about, but my controllers don't have any trouble detecting
device removal during suspend.

> a device is removed during suspend. Specifically,when we
> resume from suspend the EHCI controller maintaining the
> USB state (FLAG_CF is 1 Current Connect Status is 1) but
> a USB device (like a USB camera on rk3288) may have been
> disconnected actually.
>
> Let's add a quirk to force ehci to go into the
> usb_root_hub_lost_power() path and reset after resume.
> This should generally reset the whole controller and all
> ports and initialize everything cleanly again, and bring
> the devices back up.

Isn't this solution too extreme? What if the device was a flash
storage drive and it wasn't unplugged during suspend? This patch would
force it to be removed, messing up any mounted filesystems, when there
was no need.

Can you find a better way to work around the problem?

Alan Stern



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