Messages in this thread | | | Date | Thu, 25 Apr 2013 14:33:06 +0800 | From | Adam Lee <> | Subject | Re: [PATCH] Revert "V4L/DVB: uvc: Enable USB autosuspend by default on uvcvideo" |
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On Wed, Apr 24, 2013 at 11:17:52AM +0200, Laurent Pinchart wrote: > Hi Adam, > > Thanks for the patch. > > On Wednesday 24 April 2013 15:57:19 adam.lee@canonical.com wrote: > > From: Adam Lee <adam.lee@canonical.com> > > > > This reverts commit 3dae8b41dc5651f8eb22cf310e8b116480ba25b7. > > > > 1, I do have a Chicony webcam, implements autosuspend in a broken way, > > make `poweroff` performs rebooting when its autosuspend enabled. > > > > 2, There are other webcams which don't support autosuspend too, like > > https://patchwork.kernel.org/patch/2356141/ > > > > 3, kernel removed USB_QUIRK_NO_AUTOSUSPEND in > > a691efa9888e71232dfb4088fb8a8304ffc7b0f9, because autosuspend is > > disabled by default. > > > > So, we need to disable autosuspend in uvcvideo, maintaining a quirk list > > only for uvcvideo is not a good idea. > > I've received very few bug reports about broken auto-suspend support in UVC > devices. Most of them could be solved by setting the RESET_RESUME quirk in USB > core, only the Creative Live! Cam Optia AF required a quirk in the uvcvideo > driver. I would thus rather use the available quirks (USB_QUIRK_RESET_RESUME > if possible, UVC_QUIRK_DISABLE_AUTOSUSPEND otherwise) than killing power > management for the vast majority of webcams that behave correctly.
Here comes another one, integrated Chicony webcam 04f2:b39f, its autosuspend makes `poweroff` performs rebooting at the laptop I'm working on. I tried USB_QUIRK_RESET_RESUME, not helping.
The quirks list will go longer and longer absolutely, do uvcvideo wanna maintain that? And why only uvcvideo do this in kernel space which against general USB module?
I still suggest we disable it by default, people can enable it in udev just like almost all distroes do for udisks. Please consider about it.
-- Regards, Adam Lee Hardware Enablement
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