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From:   Takashi Iwai <tiwai@suse.de>
To:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     Eric Anholt <eric@anholt.net>,
        Stefan Wahren <stefan.wahren@i2se.com>,
        linux-rpi-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH 17/29] staging: bcm2835-audio: Add 10ms period constraint
Date:   Tue,  4 Sep 2018 17:58:46 +0200
Message-Id: <20180904155858.8001-18-tiwai@suse.de>
In-Reply-To: <20180904155858.8001-1-tiwai@suse.de>
References: <20180904155858.8001-1-tiwai@suse.de>
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

It seems that the resolution of vc04 callback is in 10 msec; i.e. the
minimal period size is also 10 msec.

This patch adds the corresponding hw constraint.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
index 9659c25b9f9d..6d89db6e14e4 100644
--- a/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
+++ b/drivers/staging/vc04_services/bcm2835-audio/bcm2835-pcm.c
@@ -145,6 +145,11 @@ static int snd_bcm2835_playback_open_generic(
 				   SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
 				   16);
 
+	/* position update is in 10ms order */
+	snd_pcm_hw_constraint_minmax(runtime,
+				     SNDRV_PCM_HW_PARAM_PERIOD_TIME,
+				     10 * 1000, UINT_MAX);
+
 	chip->alsa_stream[idx] = alsa_stream;
 
 	chip->opened |= (1 << idx);
-- 
2.18.0