From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Delvare Subject: Re: [PATCH 2/2 v2] i2c,algo: handle timeout correctly Date: Fri, 6 Feb 2009 21:51:11 +0100 Message-ID: <20090206215111.60c83bd0@hyperion.delvare> References: <4984688B.2090805@gmail.com> <20090201114121.6448a3c9@hyperion.delvare> <498760F7.6020005@gmail.com> <20090202225309.359e77d6@hyperion.delvare> <49883938.9010104@gmail.com> <20090204093402.08ddb2e8@hyperion.delvare> <4989BD34.9050406@gmail.com> <498C3712.2000904@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <498C3712.2000904-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Roel Kluin Cc: ben-linux-elnMNo+KYs3YtjvyW6yDsg@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, ebrower-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org List-Id: linux-i2c@vger.kernel.org On Fri, 06 Feb 2009 14:11:46 +0100, Roel Kluin wrote: > Let's first adress the other issues at hand. > This patch should be applied on top of my previous cleanup patch Agreed. > > --------------------------->8---------------------8<--------------------------- > With a postfix decrement these timeouts reach -1 rather than 0, but after the > loop it is tested whether they have become 0. > > As pointed out by Jean Delvare, the msg_num should be tested before the timeout. > With the current order, you could exit with a timeout error while all the > messages were successfully transferred. > > Signed-off-by: Roel Kluin > --- > diff --git a/drivers/i2c/algos/i2c-algo-pcf.c b/drivers/i2c/algos/i2c-algo-pcf.c > index ce916d7..2862f11 100644 > --- a/drivers/i2c/algos/i2c-algo-pcf.c > +++ b/drivers/i2c/algos/i2c-algo-pcf.c > @@ -115,15 +115,17 @@ static int wait_for_bb(struct i2c_algo_pcf_data *adap) > > status = get_pcf(adap, 1); > > - while (timeout-- && !(status & I2C_PCF_BB)) { > + while (!(status & I2C_PCF_BB) && --timeout) { > udelay(100); /* wait for 100 us */ > status = get_pcf(adap, 1); > } > > - if (timeout <= 0) > + if (timeout == 0) { > printk(KERN_ERR "Timeout waiting for Bus Busy\n"); > + return -ETIMEDOUT; > + } > > - return timeout <= 0; > + return 0; > } > > static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) > @@ -133,7 +135,7 @@ static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) > > *status = get_pcf(adap, 1); > > - while (timeout-- && (*status & I2C_PCF_PIN)) { > + while ((*status & I2C_PCF_PIN) && --timeout) { > adap->waitforpin(adap->data); > *status = get_pcf(adap, 1); > } > @@ -142,10 +144,10 @@ static int wait_for_pin(struct i2c_algo_pcf_data *adap, int *status) > return -EINTR; > } > > - if (timeout <= 0) > - return -1; > - else > - return 0; > + if (timeout == 0) > + return -ETIMEDOUT; > + > + return 0; > } > > /* Applied, thanks. It would be great if Eric (or anyone with a PCF8584-based adapter) could test the two patches, just to make sure we didn't accidentally break anything: ftp://ftp.kernel.org/pub/linux/kernel/people/jdelvare/linux-2.6/jdelvare-i2c/i2c-algo-pcf-01-style-cleanups.patch ftp://ftp.kernel.org/pub/linux/kernel/people/jdelvare/linux-2.6/jdelvare-i2c/i2c-algo-pcf-02-handle-timeout-correctly.patch -- Jean Delvare