From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail-ea0-f171.google.com ([209.85.215.171]:45396 "EHLO mail-ea0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751001AbaAELSf (ORCPT ); Sun, 5 Jan 2014 06:18:35 -0500 Received: by mail-ea0-f171.google.com with SMTP id h10so7370232eak.16 for ; Sun, 05 Jan 2014 03:18:33 -0800 (PST) Message-ID: <52C93FCD.2010507@googlemail.com> Date: Sun, 05 Jan 2014 12:19:41 +0100 From: =?ISO-8859-15?Q?Frank_Sch=E4fer?= MIME-Version: 1.0 To: Mauro Carvalho Chehab , unlisted-recipients:; CC: Linux Media Mailing List , Mauro Carvalho Chehab Subject: Re: [PATCH v4 12/22] [media] em28xx: properly implement AC97 wait code References: <1388832951-11195-1-git-send-email-m.chehab@samsung.com> <1388832951-11195-13-git-send-email-m.chehab@samsung.com> In-Reply-To: <1388832951-11195-13-git-send-email-m.chehab@samsung.com> Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: Am 04.01.2014 11:55, schrieb Mauro Carvalho Chehab: > Instead of assuming that msleep() is precise, use a jiffies > based code to wait for AC97 to be available. > > Signed-off-by: Mauro Carvalho Chehab > --- > drivers/media/usb/em28xx/em28xx-core.c | 7 +++++-- > drivers/media/usb/em28xx/em28xx.h | 5 ++++- > 2 files changed, 9 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/usb/em28xx/em28xx-core.c b/drivers/media/usb/em28xx/em28xx-core.c > index 818248d3fd28..36b2f1ab4474 100644 > --- a/drivers/media/usb/em28xx/em28xx-core.c > +++ b/drivers/media/usb/em28xx/em28xx-core.c > @@ -23,6 +23,7 @@ > */ > > #include > +#include > #include > #include > #include > @@ -254,16 +255,18 @@ EXPORT_SYMBOL_GPL(em28xx_toggle_reg_bits); > */ > static int em28xx_is_ac97_ready(struct em28xx *dev) > { > - int ret, i; > + unsigned long timeout = jiffies + msecs_to_jiffies(EM2800_AC97_XFER_TIMEOUT); > + int ret; > > /* Wait up to 50 ms for AC97 command to complete */ > - for (i = 0; i < 10; i++, msleep(5)) { > + while (time_is_after_jiffies(timeout)) { time_is_before_jiffies(timeout) > ret = em28xx_read_reg(dev, EM28XX_R43_AC97BUSY); > if (ret < 0) > return ret; > > if (!(ret & 0x01)) > return 0; > + msleep (5); > } > > em28xx_warn("AC97 command still being executed: not handled properly!\n"); > diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h > index 9d6f43e4681f..ac79501f5d9f 100644 > --- a/drivers/media/usb/em28xx/em28xx.h > +++ b/drivers/media/usb/em28xx/em28xx.h > @@ -182,9 +182,12 @@ > > #define EM28XX_INTERLACED_DEFAULT 1 > > -/* time in msecs to wait for i2c writes to finish */ > +/* time in msecs to wait for i2c xfers to finish */ > #define EM2800_I2C_XFER_TIMEOUT 20 > > +/* time in msecs to wait for AC97 xfers to finish */ > +#define EM2800_AC97_XFER_TIMEOUT 100 > + I applies to all chips supporting AC97 audio, so call it EM28XX_AC97_XFER_TIMEOUT. Why did you increase the timeout from 50ms to 100ms ? 50ms already seems to be a lot ! IIRC, the problem you are trying to fix is that the chip sometimes is not yet ready when probing. But that should be solved with a single sleep before accessing the AC97 chip for the first time instead ?! > /* max. number of button state polling addresses */ > #define EM28XX_NUM_BUTTON_ADDRESSES_MAX 5 >