* Re: [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection
2011-06-30 17:29 [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection Guenter Roeck
@ 2011-07-03 8:14 ` Jean Delvare
2011-07-03 16:27 ` Guenter Roeck
` (2 subsequent siblings)
3 siblings, 0 replies; 5+ messages in thread
From: Jean Delvare @ 2011-07-03 8:14 UTC (permalink / raw)
To: lm-sensors
Hi Guenter,
On Thu, 30 Jun 2011 10:29:52 -0700, Guenter Roeck wrote:
> Some PMBus devices return no error when reading fan speed registers, but don't
> really support fans. Strengthen fan detection by also checking if fan
> configuration registers exist.
>
> Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
> ---
> drivers/hwmon/pmbus.c | 6 ++++--
> 1 files changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/hwmon/pmbus.c b/drivers/hwmon/pmbus.c
> index 98e2e28..b0ea00b 100644
> --- a/drivers/hwmon/pmbus.c
> +++ b/drivers/hwmon/pmbus.c
> @@ -47,12 +47,14 @@ static void pmbus_find_sensor_groups(struct i2c_client *client,
> if (info->func[0]
> && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
> info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
> - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
> + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> info->func[0] |= PMBUS_HAVE_FAN12;
> if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
> info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
> }
> - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
> + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> info->func[0] |= PMBUS_HAVE_FAN34;
> if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
> info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
Then wouldn't it be sufficient to only test PMBUS_FAN_CONFIG_12 and
PMBUS_FAN_CONFIG_34, respectively? This would make the function
somewhat faster.
--
Jean Delvare
_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection
2011-06-30 17:29 [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection Guenter Roeck
2011-07-03 8:14 ` Jean Delvare
@ 2011-07-03 16:27 ` Guenter Roeck
2011-07-03 18:25 ` Jean Delvare
2011-07-03 20:20 ` Guenter Roeck
3 siblings, 0 replies; 5+ messages in thread
From: Guenter Roeck @ 2011-07-03 16:27 UTC (permalink / raw)
To: lm-sensors
Hi Jean,
On Sun, Jul 03, 2011 at 04:14:32AM -0400, Jean Delvare wrote:
> Hi Guenter,
>
> On Thu, 30 Jun 2011 10:29:52 -0700, Guenter Roeck wrote:
> > Some PMBus devices return no error when reading fan speed registers, but don't
> > really support fans. Strengthen fan detection by also checking if fan
> > configuration registers exist.
> >
> > Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
> > ---
> > drivers/hwmon/pmbus.c | 6 ++++--
> > 1 files changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/hwmon/pmbus.c b/drivers/hwmon/pmbus.c
> > index 98e2e28..b0ea00b 100644
> > --- a/drivers/hwmon/pmbus.c
> > +++ b/drivers/hwmon/pmbus.c
> > @@ -47,12 +47,14 @@ static void pmbus_find_sensor_groups(struct i2c_client *client,
> > if (info->func[0]
> > && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
> > info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
> > - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> > + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
> > + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> > info->func[0] |= PMBUS_HAVE_FAN12;
> > if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
> > info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
> > }
> > - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> > + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
> > + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> > info->func[0] |= PMBUS_HAVE_FAN34;
> > if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
> > info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
>
> Then wouldn't it be sufficient to only test PMBUS_FAN_CONFIG_12 and
> PMBUS_FAN_CONFIG_34, respectively? This would make the function
> somewhat faster.
I'd rather keep both. Devices should not return a valid value or should at least set
the command error flag in the status register if they don't support fans and the fan speed
register is read. If I can't trust that (and I can't because Intersil devices do just that),
I can not trust the configuration register either.
Thanks,
Guenter
_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection
2011-06-30 17:29 [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection Guenter Roeck
2011-07-03 8:14 ` Jean Delvare
2011-07-03 16:27 ` Guenter Roeck
@ 2011-07-03 18:25 ` Jean Delvare
2011-07-03 20:20 ` Guenter Roeck
3 siblings, 0 replies; 5+ messages in thread
From: Jean Delvare @ 2011-07-03 18:25 UTC (permalink / raw)
To: lm-sensors
On Sun, 3 Jul 2011 09:27:46 -0700, Guenter Roeck wrote:
> Hi Jean,
>
> On Sun, Jul 03, 2011 at 04:14:32AM -0400, Jean Delvare wrote:
> > Hi Guenter,
> >
> > On Thu, 30 Jun 2011 10:29:52 -0700, Guenter Roeck wrote:
> > > Some PMBus devices return no error when reading fan speed registers, but don't
> > > really support fans. Strengthen fan detection by also checking if fan
> > > configuration registers exist.
> > >
> > > Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
> > > ---
> > > drivers/hwmon/pmbus.c | 6 ++++--
> > > 1 files changed, 4 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/drivers/hwmon/pmbus.c b/drivers/hwmon/pmbus.c
> > > index 98e2e28..b0ea00b 100644
> > > --- a/drivers/hwmon/pmbus.c
> > > +++ b/drivers/hwmon/pmbus.c
> > > @@ -47,12 +47,14 @@ static void pmbus_find_sensor_groups(struct i2c_client *client,
> > > if (info->func[0]
> > > && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
> > > info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
> > > - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> > > + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
> > > + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> > > info->func[0] |= PMBUS_HAVE_FAN12;
> > > if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
> > > info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
> > > }
> > > - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> > > + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
> > > + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> > > info->func[0] |= PMBUS_HAVE_FAN34;
> > > if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
> > > info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
> >
> > Then wouldn't it be sufficient to only test PMBUS_FAN_CONFIG_12 and
> > PMBUS_FAN_CONFIG_34, respectively? This would make the function
> > somewhat faster.
>
> I'd rather keep both. Devices should not return a valid value or should at least set
> the command error flag in the status register if they don't support fans and the fan speed
> register is read. If I can't trust that (and I can't because Intersil devices do just that),
> I can not trust the configuration register either.
I think that what worries me is the asymmetry. Is it not possible for a
device to have FAN_SPEED_2 and not FAN_SPEED_1? If not then your code
is fine, I agree. But if it is possible, then we need smarter code.
But also note that I don't know a thing about PMBus, so there may be
nothing to worry about.
--
Jean Delvare
_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection
2011-06-30 17:29 [lm-sensors] [PATCH 3/4] hwmon: (pmbus) Improve fan detection Guenter Roeck
` (2 preceding siblings ...)
2011-07-03 18:25 ` Jean Delvare
@ 2011-07-03 20:20 ` Guenter Roeck
3 siblings, 0 replies; 5+ messages in thread
From: Guenter Roeck @ 2011-07-03 20:20 UTC (permalink / raw)
To: lm-sensors
On Sun, Jul 03, 2011 at 02:25:03PM -0400, Jean Delvare wrote:
> On Sun, 3 Jul 2011 09:27:46 -0700, Guenter Roeck wrote:
> > Hi Jean,
> >
> > On Sun, Jul 03, 2011 at 04:14:32AM -0400, Jean Delvare wrote:
> > > Hi Guenter,
> > >
> > > On Thu, 30 Jun 2011 10:29:52 -0700, Guenter Roeck wrote:
> > > > Some PMBus devices return no error when reading fan speed registers, but don't
> > > > really support fans. Strengthen fan detection by also checking if fan
> > > > configuration registers exist.
> > > >
> > > > Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
> > > > ---
> > > > drivers/hwmon/pmbus.c | 6 ++++--
> > > > 1 files changed, 4 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/drivers/hwmon/pmbus.c b/drivers/hwmon/pmbus.c
> > > > index 98e2e28..b0ea00b 100644
> > > > --- a/drivers/hwmon/pmbus.c
> > > > +++ b/drivers/hwmon/pmbus.c
> > > > @@ -47,12 +47,14 @@ static void pmbus_find_sensor_groups(struct i2c_client *client,
> > > > if (info->func[0]
> > > > && pmbus_check_byte_register(client, 0, PMBUS_STATUS_INPUT))
> > > > info->func[0] |= PMBUS_HAVE_STATUS_INPUT;
> > > > - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> > > > + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_12) &&
> > > > + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_1)) {
> > > > info->func[0] |= PMBUS_HAVE_FAN12;
> > > > if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_12))
> > > > info->func[0] |= PMBUS_HAVE_STATUS_FAN12;
> > > > }
> > > > - if (pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> > > > + if (pmbus_check_byte_register(client, 0, PMBUS_FAN_CONFIG_34) &&
> > > > + pmbus_check_word_register(client, 0, PMBUS_READ_FAN_SPEED_3)) {
> > > > info->func[0] |= PMBUS_HAVE_FAN34;
> > > > if (pmbus_check_byte_register(client, 0, PMBUS_STATUS_FAN_34))
> > > > info->func[0] |= PMBUS_HAVE_STATUS_FAN34;
> > >
> > > Then wouldn't it be sufficient to only test PMBUS_FAN_CONFIG_12 and
> > > PMBUS_FAN_CONFIG_34, respectively? This would make the function
> > > somewhat faster.
> >
> > I'd rather keep both. Devices should not return a valid value or should at least set
> > the command error flag in the status register if they don't support fans and the fan speed
> > register is read. If I can't trust that (and I can't because Intersil devices do just that),
> > I can not trust the configuration register either.
>
> I think that what worries me is the asymmetry. Is it not possible for a
> device to have FAN_SPEED_2 and not FAN_SPEED_1? If not then your code
> is fine, I agree. But if it is possible, then we need smarter code.
>
With PMBus, everything is possible ;). It is pretty much impossible to cover all
possible variants. Who would have thought that the fan speed register would return
a value even though the device doesn't support fans ?
My approach is to get my hand on as many PMBus devices as possible and improve the code
whenever I find something new. So far the manufacturers have almost never failed
to surprise me - it is almost as if there is a competition to find as many
interpretations of the standard as possible.
I have some work to do to improve fan support anyway, so I'll keep this in mind.
I think for the time being we are good.
> But also note that I don't know a thing about PMBus, so there may be
> nothing to worry about.
>
Not even sure if it is _possible_ to completely understand PMBus ...
Thanks,
Guenter
_______________________________________________
lm-sensors mailing list
lm-sensors@lm-sensors.org
http://lists.lm-sensors.org/mailman/listinfo/lm-sensors
^ permalink raw reply [flat|nested] 5+ messages in thread