> From: Felipe Balbi [mailto:balbi@xxxxxx] > Sent: Tuesday, May 06, 2014 11:37 AM > > On Tue, May 06, 2014 at 06:21:02PM +0000, Paul Zimmerman wrote: > > > From: dinguyen@xxxxxxxxxx [mailto:dinguyen@xxxxxxxxxx] > > > Sent: Monday, May 05, 2014 3:23 PM > > > > > > Even though the IP supports Descriptor DMA mode, it does not support SPLIT > > > transactions in this mode. Since the driver can get the Descriptor DMA mode > > > support from hardware, the driver in its currently form cannot fully support > > > LS/FS devices connected to a HS Hub when Descriptor DMA mode is enabled in the > > > driver. Thus, we give the option to disable Descriptor DMA from device tree. > > > > Hi Dinh, > > > > Instead of this patch, how about if we make the driver default to buffer > > DMA mode instead, and if anyone wants to use descriptor DMA mode, they > > can add a DT property for that? I don't think anyone will want that, > > since as you say it doesn't fully support LS/FS devices in that mode. > > > > The driver originally worked like that. I guess the default got changed by > > one of Matthijs' patches, and I didn't notice it. > > if this is the case, I guess you could call it a regression - well, it > _did_ break LS/FS use cases - and still merge it during the -rc cycle. Well, the change from Matthijs went in on August 30th last year. So it's not exactly a recent regression ;) -- Paul -- 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
