| Message ID | 1526366456-20470-5-git-send-email-sriramx.periyasamy@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Tue, 15 May 2018 08:40:56 +0200, Sriram Periyasamy wrote: > > From: Pardha Saradhi K <pardha.saradhi.kesapragada@intel.com> > > Check if the DMA Channel is already stopped. There is no need > to stop it again if stopped. > > Signed-off-by: Pardha Saradhi K <pardha.saradhi.kesapragada@intel.com> > Signed-off-by: Sriram Periyasamy <sriramx.periyasamy@intel.com> > --- > sound/hda/hdac_stream.c | 5 +++++ > 1 file changed, 5 insertions(+) > > diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c > index aa8a2884289f..c1810eb7212b 100644 > --- a/sound/hda/hdac_stream.c > +++ b/sound/hda/hdac_stream.c > @@ -89,6 +89,11 @@ void snd_hdac_stream_clear(struct hdac_stream *azx_dev) > int timeout = 300; > unsigned char val; > > + /* check if the DMA is already stopped */ > + val = snd_hdac_stream_readb(azx_dev, SD_CTL) & SD_CTL_DMA_START; > + if (!val) > + return; > + > snd_hdac_stream_updateb(azx_dev, SD_CTL, > SD_CTL_DMA_START | SD_INT_MASK, 0); Here we call snd_hdac_stream_updateb(), so we don't write unnecessarily. And, if any shortcut is wanted, rather check azx_dev->running flag instead of the h/w register. The former is significantly cheaper. thanks, Takashi
diff --git a/sound/hda/hdac_stream.c b/sound/hda/hdac_stream.c index aa8a2884289f..c1810eb7212b 100644 --- a/sound/hda/hdac_stream.c +++ b/sound/hda/hdac_stream.c @@ -89,6 +89,11 @@ void snd_hdac_stream_clear(struct hdac_stream *azx_dev) int timeout = 300; unsigned char val; + /* check if the DMA is already stopped */ + val = snd_hdac_stream_readb(azx_dev, SD_CTL) & SD_CTL_DMA_START; + if (!val) + return; + snd_hdac_stream_updateb(azx_dev, SD_CTL, SD_CTL_DMA_START | SD_INT_MASK, 0);