HI Mathias, >-----Original Message----- >From: Mathias Nyman [mailto:mathias.nyman@xxxxxxxxxxxxxxx] >Sent: Thursday, June 01, 2017 6:51 PM >To: Anurag Kumar Vulisha <anuragku@xxxxxxxxxx>; mathias.nyman@xxxxxxxxx; >gregkh@xxxxxxxxxxxxxxxxxxx >Cc: linux-usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Anirudha Sarangi ><anirudh@xxxxxxxxxx>; Anurag Kumar Vulisha <anuragku@xxxxxxxxxx> >Subject: Re: [LINUX PATCH] usb: xhci: Add toggle cycle bit for the last seg trb >when cached ring is used > >On 31.05.2017 16:41, Anurag Kumar Vulisha wrote: >> At present USB 2.0 cameras fail to play when run for 2nd time or greater. >> This issue occurs only when previous endpoint cached ring is used >> instead of allocating a new endpoint ring. The root cause of the >> problem narrows down to the Toggle bit, which is not getting set on >> the last trb of the cached ring last segment. When the controller >> fetches the last link trb with no toggle bit set, abnormal behaviour is generated. >> This patch solves that problem by adding the TOGGLE bit for the last >> trb of the last segment of the cached ring. >> >> Signed-off-by: Anurag Kumar Vulisha <anuragku@xxxxxxxxxx> > >Thanks, nice catch. > >I'm thinking about removing the whole endpoint ring caching instead. > >We are using more memory by caching the rings instead of freeing them, >especially as we always try to allocate a new ring and only use the cached ones >when we fail to allocate a new ring. > >Would you be willing to test a patch that removes the ring cache completely with >your setup? > Thanks for reviewing the patch. I completely agree with you. But I think instead of completely removing the cached ring , can we modify the code to use cached ring and try to allocate new ep ring on failure to get cached ring. I have previously sent the patch for doing this https://lkml.org/lkml/2017/2/22/336 But anyways I am ready to test the changes with my platform. Please correct me if I am wrong Thanks, Anurag Kumar Vulisha >Thanks >Mathias > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
