From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Subject: Re: [PATCH 1/2] usb: dwc2: Option to disable dma descriptor mode Date: Tue, 6 May 2014 13:36:30 -0500 Message-ID: <20140506183630.GA31117@saruman.home> References: <1399328585-30949-1-git-send-email-dinguyen@altera.com> Reply-To: Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="jI8keyz6grp/JLjh" Return-path: Content-Disposition: inline In-Reply-To: Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Paul Zimmerman Cc: "dinguyen-EIB2kfCEclfQT0dZR+AlfA@public.gmane.org" , "robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org" , "pawel.moll-5wv7dgnIgG8@public.gmane.org" , "mark.rutland-5wv7dgnIgG8@public.gmane.org" , "ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org" , "galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org" , "dinh.linux-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org --jI8keyz6grp/JLjh Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 06, 2014 at 06:21:02PM +0000, Paul Zimmerman wrote: > > From: dinguyen-EIB2kfCEclfQT0dZR+AlfA@public.gmane.org [mailto:dinguyen-EIB2kfCEclfQT0dZR+AlfA@public.gmane.org] > > Sent: Monday, May 05, 2014 3:23 PM > >=20 > > Even though the IP supports Descriptor DMA mode, it does not support SP= LIT > > transactions in this mode. Since the driver can get the Descriptor DMA = mode > > support from hardware, the driver in its currently form cannot fully su= pport > > 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. >=20 > Hi Dinh, >=20 > 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. >=20 > 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. cheers --=20 balbi --jI8keyz6grp/JLjh Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJTaSuuAAoJEIaOsuA1yqREF24P/i3JFLf9H+hlanczWj4lP5A8 M72iYa1qBVjSjsVyRaMkhmaXIc/3JjF05Lc06Z/ym5EfHzB92KHmeKWgzSLTPIpu 4N2tK5APUZ9ksh+CTCCXD42qjvhowQqVCKtKSJZQ8JAdKDDEu2fsztRYATwtCS03 iEQFvru5FJqR8ZhDB2yO4eh2hQyOtuF1ym3HBzywHC3JgN6v2hCGp+wOMG/DiLzv as/fqd3mOLOxO85pMC+wc4eLRMxY8ewfxSPmotozPNI1XMmRe3nVPsszt8AOaWaj qmYraAHsX3NzH1neLbX0gF+Zab3VRdwE1kuNhegHpVK9JG3rMk/dHYeqTA04NQi+ PvI//VamuhnjdwTWYxK22N+s19zgteJTK5Z2/KMb8pkj2RTfTLh/Nm9LkjIUzA6N lNlS6qoXEpvzWg8Vicd6rrPNlGtYemAgMFvXXykOlwckDBp2KS1XBashBhicQnu9 coQeNo3pGKL0Vcbp5wklhli6BGjF6FGdbm/fWBAoXAuS9DsqmFw+0tucQ46F4ZXI JJqtJxydzZqapfYYV0mqkOVQvlv5Bt24gcr1mH+B3tY3brpbhUuYovIvKJ/5Rs9k pzwzey1Tj7AhPMUf10dKkZTJwgU++6oSVcWTIQfIWhL6tqd4wriMq05mvaSHa+an AyqCOfJfx5Bja+tEKZoy =8tZG -----END PGP SIGNATURE----- --jI8keyz6grp/JLjh-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html