Re: [PATCH 1/1] platform/x86: thinkpad_acpi: skip invalid fan speed

Re: [PATCH 1/1] platform/x86: thinkpad_acpi: skip invalid fan speed

[Hans de Goede]

Hi,

On 10/14/22 23:17, Jelle van der Waa wrote:
> 65535 is most likely an invalid read.

I wonder if it is an invalid read, or if it actually is a reserved value
which means "FAN_NOT_PRESENT"

I'm tempted to add:

#define FAN_NOT_PRESENT		65535

and then change the check to:

			if (res >= 0 && speed != FAN_NOT_PRESENT) {


That would make the code more logical to read.

Jelle, can you make this change for v2 ? Also please Cc: platform-driver-x86@vger.kernel.org
for v2.

Mark, what do you think of this change (and of adding the
FAN_NOT_PRESENT define) ?

Regards,

Hans



> 
> Signed-off-by: Jelle van der Waa <jvanderwaa@redhat.com>
> 
> ---
> 
> Cc: Mark Pearson <markpearson@lenovo.com>
> ---
>  drivers/platform/x86/thinkpad_acpi.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index 6a823b850a77..7e0f72dc53b7 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -8876,7 +8876,7 @@ static int __init fan_init(struct ibm_init_struct *iibm)
>  			/* Try and probe the 2nd fan */
>  			tp_features.second_fan = 1; /* needed for get_speed to work */
>  			res = fan2_get_speed(&speed);
> -			if (res >= 0) {
> +			if (res >= 0 && speed != 65535) {
>  				/* It responded - so let's assume it's there */
>  				tp_features.second_fan = 1;
>  				tp_features.second_fan_ctl = 1;

Re: [External] Re: [PATCH 1/1] platform/x86: thinkpad_acpi: skip invalid fan speed

[Mark Pearson]

HI Hans

On 2022-10-15 10:22, Hans de Goede wrote:
> Hi,
> 
> On 10/14/22 23:17, Jelle van der Waa wrote:
>> 65535 is most likely an invalid read.
> 
> I wonder if it is an invalid read, or if it actually is a reserved value
> which means "FAN_NOT_PRESENT"
> 
> I'm tempted to add:
> 
> #define FAN_NOT_PRESENT		65535
> 
> and then change the check to:
> 
> 			if (res >= 0 && speed != FAN_NOT_PRESENT) {
> 
> 
> That would make the code more logical to read.
> 
> Jelle, can you make this change for v2 ? Also please Cc: platform-driver-x86@vger.kernel.org
> for v2.
> 
> Mark, what do you think of this change (and of adding the
> FAN_NOT_PRESENT define) ?
Looks good to me.

I've asked the FW team to see if they can confirm if this will be
standard behaviour (it's not defined in the spec that I have) and will
update if I get an answer. But regardless I think it makes sense.

Mark

> 
> Regards,
> 
> Hans
> 
> 
> 
>>
>> Signed-off-by: Jelle van der Waa <jvanderwaa@redhat.com>
>>
>> ---
>>
>> Cc: Mark Pearson <markpearson@lenovo.com>
>> ---
>>  drivers/platform/x86/thinkpad_acpi.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
>> index 6a823b850a77..7e0f72dc53b7 100644
>> --- a/drivers/platform/x86/thinkpad_acpi.c
>> +++ b/drivers/platform/x86/thinkpad_acpi.c
>> @@ -8876,7 +8876,7 @@ static int __init fan_init(struct ibm_init_struct *iibm)
>>  			/* Try and probe the 2nd fan */
>>  			tp_features.second_fan = 1; /* needed for get_speed to work */
>>  			res = fan2_get_speed(&speed);
>> -			if (res >= 0) {
>> +			if (res >= 0 && speed != 65535) {
>>  				/* It responded - so let's assume it's there */
>>  				tp_features.second_fan = 1;
>>  				tp_features.second_fan_ctl = 1;
> 

[PATCH] platform/x86: thinkpad_acpi: skip invalid fan speed

[Jelle van der Waa]

65535 is most likely an invalid read.

Signed-off-by: Jelle van der Waa <jvanderwaa@redhat.com>

---

Cc: Mark Pearson <markpearson@lenovo.com>
---
 drivers/platform/x86/thinkpad_acpi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 6a823b850a77..20e5c043a8e8 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -263,6 +263,8 @@ enum tpacpi_hkey_event_t {
 #define TPACPI_DBG_BRGHT	0x0020
 #define TPACPI_DBG_MIXER	0x0040
 
+#define FAN_NOT_PRESENT		65535
+
 #define strlencmp(a, b) (strncmp((a), (b), strlen(b)))
 
 
@@ -8876,7 +8878,7 @@ static int __init fan_init(struct ibm_init_struct *iibm)
 			/* Try and probe the 2nd fan */
 			tp_features.second_fan = 1; /* needed for get_speed to work */
 			res = fan2_get_speed(&speed);
-			if (res >= 0) {
+			if (res >= 0 && speed != FAN_NOT_PRESENT) {
 				/* It responded - so let's assume it's there */
 				tp_features.second_fan = 1;
 				tp_features.second_fan_ctl = 1;
-- 
2.38.1

Re: [PATCH] platform/x86: thinkpad_acpi: skip invalid fan speed

[Hans de Goede]

Hi,

On 10/19/22 21:47, Jelle van der Waa wrote:
> 65535 is most likely an invalid read.
> 
> Signed-off-by: Jelle van der Waa <jvanderwaa@redhat.com>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

Once I've run some tests on this branch the patches there will be
added to the platform-drivers-x86/for-next branch and eventually
will be included in the pdx86 pull-request to Linus for the next
merge-window.

Regards,

Hans


> 
> ---
> 
> Cc: Mark Pearson <markpearson@lenovo.com>
> ---
>  drivers/platform/x86/thinkpad_acpi.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index 6a823b850a77..20e5c043a8e8 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -263,6 +263,8 @@ enum tpacpi_hkey_event_t {
>  #define TPACPI_DBG_BRGHT	0x0020
>  #define TPACPI_DBG_MIXER	0x0040
>  
> +#define FAN_NOT_PRESENT		65535
> +
>  #define strlencmp(a, b) (strncmp((a), (b), strlen(b)))
>  
>  
> @@ -8876,7 +8878,7 @@ static int __init fan_init(struct ibm_init_struct *iibm)
>  			/* Try and probe the 2nd fan */
>  			tp_features.second_fan = 1; /* needed for get_speed to work */
>  			res = fan2_get_speed(&speed);
> -			if (res >= 0) {
> +			if (res >= 0 && speed != FAN_NOT_PRESENT) {
>  				/* It responded - so let's assume it's there */
>  				tp_features.second_fan = 1;
>  				tp_features.second_fan_ctl = 1;