From mboxrd@z Thu Jan 1 00:00:00 1970 From: Govindraj Subject: Re: [PATCH 2/2] Add DMA support for the sh-sci.c serial driver Date: Fri, 19 Feb 2010 15:42:52 +0530 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: Sender: linux-sh-owner@vger.kernel.org To: Guennadi Liakhovetski Cc: "linux-sh@vger.kernel.org" , Magnus Damm , Dan Williams , linux-serial@vger.kernel.org List-Id: linux-serial@vger.kernel.org On Fri, Feb 19, 2010 at 3:26 PM, Guennadi Liakhovetski wrote: > On Fri, 19 Feb 2010, Govindraj wrote: > >> > + =A0 =A0 =A0 chan =3D dma_request_channel(mask, filter, param); >> > + =A0 =A0 =A0 dev_dbg(port->dev, "%s: RX: got channel %p\n", __fun= c__, chan); >> >> >> If dma channel allocation fails how this scenario will be handled, >> There is an possibility of dma_request_channel returning -EBUSY, > > Really? How? I thought it could only return a pointer to a channel or= a > NULL? And if it fails, i.e., chan =3D=3D NULL, the whole code just st= ays > inactive and the driver falls back to normal PIO. Sorry I missed this part: if (s->chan_tx) { if (s->chan_rx) { > Thanks > Guennadi > --- > Guennadi Liakhovetski, Ph.D. > Freelance Open-Source Software Developer > http://www.open-technology.de/ > --- Regards, Govindraj.R