* RE: Re: [PATCH] pps: fix poll support
@ 2025-04-03 6:06 Denis OSTERLAND-HEIM
2025-04-03 7:49 ` Rodolfo Giometti
0 siblings, 1 reply; 4+ messages in thread
From: Denis OSTERLAND-HEIM @ 2025-04-03 6:06 UTC (permalink / raw)
To: Rodolfo Giometti; +Cc: linux-kernel, stable
[-- Attachment #1: Type: text/plain, Size: 3991 bytes --]
Hi Rodolfo,
Do you think that there is a chance that this patch make it in the current merge window?
Regards Denis
-----Original Message-----
From: Rodolfo Giometti <giometti@enneenne.com>
Sent: Monday, March 3, 2025 12:54 PM
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org; Denis OSTERLAND-HEIM <denis.osterland@diehl.com>; stable@vger.kernel.org
Subject: [EXT] Re: [PATCH] pps: fix poll support
[EXTERNAL EMAIL]
On 03/03/25 09:02, Denis OSTERLAND-HEIM wrote:
> [BUG]
> A user space program that calls select/poll get always an immediate data
> ready-to-read response. As a result the intended use to wait until next
> data becomes ready does not work.
>
> User space snippet:
>
> struct pollfd pollfd = {
> .fd = open("/dev/pps0", O_RDONLY),
> .events = POLLIN|POLLERR,
> .revents = 0 };
> while(1) {
> poll(&pollfd, 1, 2000/*ms*/); // returns immediate, but should wait
> if(revents & EPOLLIN) { // always true
> struct pps_fdata fdata;
> memset(&fdata, 0, sizeof(memdata));
> ioctl(PPS_FETCH, &fdata); // currently fetches data at max speed
> }
> }
>
> [CAUSE]
> pps_cdev_poll() returns unconditionally EPOLLIN.
>
> [FIX]
> Remember the last fetch event counter and compare this value in
> pps_cdev_poll() with most recent event counter
> and return 0 if they are equal.
>
> Signed-off-by: Denis OSTERLAND-HEIM <denis.osterland@diehl.com>
> Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
Acked-by: Rodolfo Giometti <giometti@enneenne.com>
If needed. :)
> Fixes: eae9d2ba0cfc ("LinuxPPS: core support")
> CC: stable@vger.linux.org # 5.4+
> ---
> drivers/pps/pps.c | 11 +++++++++--
> include/linux/pps_kernel.h | 1 +
> 2 files changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
> index 6a02245ea35f..9463232af8d2 100644
> --- a/drivers/pps/pps.c
> +++ b/drivers/pps/pps.c
> @@ -41,6 +41,9 @@ static __poll_t pps_cdev_poll(struct file *file, poll_table *wait)
>
> poll_wait(file, &pps->queue, wait);
>
> + if (pps->last_fetched_ev == pps->last_ev)
> + return 0;
> +
> return EPOLLIN | EPOLLRDNORM;
> }
>
> @@ -186,9 +189,11 @@ static long pps_cdev_ioctl(struct file *file,
> if (err)
> return err;
>
> - /* Return the fetched timestamp */
> + /* Return the fetched timestamp and save last fetched event */
> spin_lock_irq(&pps->lock);
>
> + pps->last_fetched_ev = pps->last_ev;
> +
> fdata.info.assert_sequence = pps->assert_sequence;
> fdata.info.clear_sequence = pps->clear_sequence;
> fdata.info.assert_tu = pps->assert_tu;
> @@ -272,9 +277,11 @@ static long pps_cdev_compat_ioctl(struct file *file,
> if (err)
> return err;
>
> - /* Return the fetched timestamp */
> + /* Return the fetched timestamp and save last fetched event */
> spin_lock_irq(&pps->lock);
>
> + pps->last_fetched_ev = pps->last_ev;
> +
> compat.info.assert_sequence = pps->assert_sequence;
> compat.info.clear_sequence = pps->clear_sequence;
> compat.info.current_mode = pps->current_mode;
> diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
> index c7abce28ed29..aab0aebb529e 100644
> --- a/include/linux/pps_kernel.h
> +++ b/include/linux/pps_kernel.h
> @@ -52,6 +52,7 @@ struct pps_device {
> int current_mode; /* PPS mode at event time */
>
> unsigned int last_ev; /* last PPS event id */
> + unsigned int last_fetched_ev; /* last fetched PPS event id */
> wait_queue_head_t queue; /* PPS event queue */
>
> unsigned int id; /* PPS source unique ID */
--
GNU/Linux Solutions e-mail: giometti@enneenne.com
Linux Device Driver giometti@linux.it
Embedded Systems phone: +39 349 2432127
UNIX programming
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] pps: fix poll support
2025-04-03 6:06 Re: [PATCH] pps: fix poll support Denis OSTERLAND-HEIM
@ 2025-04-03 7:49 ` Rodolfo Giometti
2025-04-10 7:42 ` Denis OSTERLAND-HEIM
0 siblings, 1 reply; 4+ messages in thread
From: Rodolfo Giometti @ 2025-04-03 7:49 UTC (permalink / raw)
To: Denis OSTERLAND-HEIM; +Cc: linux-kernel, stable
On 03/04/25 08:06, Denis OSTERLAND-HEIM wrote:
> Hi Rodolfo,
>
> Do you think that there is a chance that this patch make it in the current merge window?
Honestly, I don't know, it's up to Greg or Andrew to proceed for inclusion.
Ciao,
Rodolfo
> -----Original Message-----
> From: Rodolfo Giometti <giometti@enneenne.com>
> Sent: Monday, March 3, 2025 12:54 PM
> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-kernel@vger.kernel.org; Denis OSTERLAND-HEIM <denis.osterland@diehl.com>; stable@vger.kernel.org
> Subject: [EXT] Re: [PATCH] pps: fix poll support
>
> [EXTERNAL EMAIL]
>
>
> On 03/03/25 09:02, Denis OSTERLAND-HEIM wrote:
>> [BUG]
>> A user space program that calls select/poll get always an immediate data
>> ready-to-read response. As a result the intended use to wait until next
>> data becomes ready does not work.
>>
>> User space snippet:
>>
>> struct pollfd pollfd = {
>> .fd = open("/dev/pps0", O_RDONLY),
>> .events = POLLIN|POLLERR,
>> .revents = 0 };
>> while(1) {
>> poll(&pollfd, 1, 2000/*ms*/); // returns immediate, but should wait
>> if(revents & EPOLLIN) { // always true
>> struct pps_fdata fdata;
>> memset(&fdata, 0, sizeof(memdata));
>> ioctl(PPS_FETCH, &fdata); // currently fetches data at max speed
>> }
>> }
>>
>> [CAUSE]
>> pps_cdev_poll() returns unconditionally EPOLLIN.
>>
>> [FIX]
>> Remember the last fetch event counter and compare this value in
>> pps_cdev_poll() with most recent event counter
>> and return 0 if they are equal.
>>
>> Signed-off-by: Denis OSTERLAND-HEIM <denis.osterland@diehl.com>
>> Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
>> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
>
> Acked-by: Rodolfo Giometti <giometti@enneenne.com>
>
> If needed. :)
>
>> Fixes: eae9d2ba0cfc ("LinuxPPS: core support")
>> CC: stable@vger.linux.org # 5.4+
>> ---
>> drivers/pps/pps.c | 11 +++++++++--
>> include/linux/pps_kernel.h | 1 +
>> 2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
>> index 6a02245ea35f..9463232af8d2 100644
>> --- a/drivers/pps/pps.c
>> +++ b/drivers/pps/pps.c
>> @@ -41,6 +41,9 @@ static __poll_t pps_cdev_poll(struct file *file, poll_table *wait)
>>
>> poll_wait(file, &pps->queue, wait);
>>
>> + if (pps->last_fetched_ev == pps->last_ev)
>> + return 0;
>> +
>> return EPOLLIN | EPOLLRDNORM;
>> }
>>
>> @@ -186,9 +189,11 @@ static long pps_cdev_ioctl(struct file *file,
>> if (err)
>> return err;
>>
>> - /* Return the fetched timestamp */
>> + /* Return the fetched timestamp and save last fetched event */
>> spin_lock_irq(&pps->lock);
>>
>> + pps->last_fetched_ev = pps->last_ev;
>> +
>> fdata.info.assert_sequence = pps->assert_sequence;
>> fdata.info.clear_sequence = pps->clear_sequence;
>> fdata.info.assert_tu = pps->assert_tu;
>> @@ -272,9 +277,11 @@ static long pps_cdev_compat_ioctl(struct file *file,
>> if (err)
>> return err;
>>
>> - /* Return the fetched timestamp */
>> + /* Return the fetched timestamp and save last fetched event */
>> spin_lock_irq(&pps->lock);
>>
>> + pps->last_fetched_ev = pps->last_ev;
>> +
>> compat.info.assert_sequence = pps->assert_sequence;
>> compat.info.clear_sequence = pps->clear_sequence;
>> compat.info.current_mode = pps->current_mode;
>> diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
>> index c7abce28ed29..aab0aebb529e 100644
>> --- a/include/linux/pps_kernel.h
>> +++ b/include/linux/pps_kernel.h
>> @@ -52,6 +52,7 @@ struct pps_device {
>> int current_mode; /* PPS mode at event time */
>>
>> unsigned int last_ev; /* last PPS event id */
>> + unsigned int last_fetched_ev; /* last fetched PPS event id */
>> wait_queue_head_t queue; /* PPS event queue */
>>
>> unsigned int id; /* PPS source unique ID */
>
--
GNU/Linux Solutions e-mail: giometti@enneenne.com
Linux Device Driver giometti@linux.it
Embedded Systems phone: +39 349 2432127
UNIX programming
^ permalink raw reply [flat|nested] 4+ messages in thread
* RE: Re: [PATCH] pps: fix poll support
2025-04-03 7:49 ` Rodolfo Giometti
@ 2025-04-10 7:42 ` Denis OSTERLAND-HEIM
2025-04-10 7:57 ` Greg Kroah-Hartman
0 siblings, 1 reply; 4+ messages in thread
From: Denis OSTERLAND-HEIM @ 2025-04-10 7:42 UTC (permalink / raw)
To: Greg Kroah-Hartman, Andrew Morton; +Cc: linux-kernel, stable, Rodolfo Giometti
Hi,
Rodolfo told me that you may bring this patch to master, so I would like to ask if there is a chance for the 6.16 merge window?
Regards Denis
-----Original Message-----
From: Rodolfo Giometti <giometti@enneenne.com>
Sent: Thursday, April 3, 2025 9:49 AM
To: Denis OSTERLAND-HEIM <denis.osterland@diehl.com>
Cc: linux-kernel@vger.kernel.org; stable@vger.kernel.org
Subject: [EXT] Re: [PATCH] pps: fix poll support
[EXTERNAL EMAIL]
On 03/04/25 08:06, Denis OSTERLAND-HEIM wrote:
> Hi Rodolfo,
>
> Do you think that there is a chance that this patch make it in the current merge window?
Honestly, I don't know, it's up to Greg or Andrew to proceed for inclusion.
Ciao,
Rodolfo
> -----Original Message-----
> From: Rodolfo Giometti <giometti@enneenne.com>
> Sent: Monday, March 3, 2025 12:54 PM
> To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-kernel@vger.kernel.org; Denis OSTERLAND-HEIM <denis.osterland@diehl.com>; stable@vger.kernel.org
> Subject: [EXT] Re: [PATCH] pps: fix poll support
>
> [EXTERNAL EMAIL]
>
>
> On 03/03/25 09:02, Denis OSTERLAND-HEIM wrote:
>> [BUG]
>> A user space program that calls select/poll get always an immediate data
>> ready-to-read response. As a result the intended use to wait until next
>> data becomes ready does not work.
>>
>> User space snippet:
>>
>> struct pollfd pollfd = {
>> .fd = open("/dev/pps0", O_RDONLY),
>> .events = POLLIN|POLLERR,
>> .revents = 0 };
>> while(1) {
>> poll(&pollfd, 1, 2000/*ms*/); // returns immediate, but should wait
>> if(revents & EPOLLIN) { // always true
>> struct pps_fdata fdata;
>> memset(&fdata, 0, sizeof(memdata));
>> ioctl(PPS_FETCH, &fdata); // currently fetches data at max speed
>> }
>> }
>>
>> [CAUSE]
>> pps_cdev_poll() returns unconditionally EPOLLIN.
>>
>> [FIX]
>> Remember the last fetch event counter and compare this value in
>> pps_cdev_poll() with most recent event counter
>> and return 0 if they are equal.
>>
>> Signed-off-by: Denis OSTERLAND-HEIM <denis.osterland@diehl.com>
>> Co-developed-by: Rodolfo Giometti <giometti@enneenne.com>
>> Signed-off-by: Rodolfo Giometti <giometti@enneenne.com>
>
> Acked-by: Rodolfo Giometti <giometti@enneenne.com>
>
> If needed. :)
>
>> Fixes: eae9d2ba0cfc ("LinuxPPS: core support")
>> CC: stable@vger.linux.org # 5.4+
>> ---
>> drivers/pps/pps.c | 11 +++++++++--
>> include/linux/pps_kernel.h | 1 +
>> 2 files changed, 10 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/pps/pps.c b/drivers/pps/pps.c
>> index 6a02245ea35f..9463232af8d2 100644
>> --- a/drivers/pps/pps.c
>> +++ b/drivers/pps/pps.c
>> @@ -41,6 +41,9 @@ static __poll_t pps_cdev_poll(struct file *file, poll_table *wait)
>>
>> poll_wait(file, &pps->queue, wait);
>>
>> +if (pps->last_fetched_ev == pps->last_ev)
>> +return 0;
>> +
>> return EPOLLIN | EPOLLRDNORM;
>> }
>>
>> @@ -186,9 +189,11 @@ static long pps_cdev_ioctl(struct file *file,
>> if (err)
>> return err;
>>
>> -/* Return the fetched timestamp */
>> +/* Return the fetched timestamp and save last fetched event */
>> spin_lock_irq(&pps->lock);
>>
>> +pps->last_fetched_ev = pps->last_ev;
>> +
>> fdata.info.assert_sequence = pps->assert_sequence;
>> fdata.info.clear_sequence = pps->clear_sequence;
>> fdata.info.assert_tu = pps->assert_tu;
>> @@ -272,9 +277,11 @@ static long pps_cdev_compat_ioctl(struct file *file,
>> if (err)
>> return err;
>>
>> -/* Return the fetched timestamp */
>> +/* Return the fetched timestamp and save last fetched event */
>> spin_lock_irq(&pps->lock);
>>
>> +pps->last_fetched_ev = pps->last_ev;
>> +
>> compat.info.assert_sequence = pps->assert_sequence;
>> compat.info.clear_sequence = pps->clear_sequence;
>> compat.info.current_mode = pps->current_mode;
>> diff --git a/include/linux/pps_kernel.h b/include/linux/pps_kernel.h
>> index c7abce28ed29..aab0aebb529e 100644
>> --- a/include/linux/pps_kernel.h
>> +++ b/include/linux/pps_kernel.h
>> @@ -52,6 +52,7 @@ struct pps_device {
>> int current_mode;/* PPS mode at event time */
>>
>> unsigned int last_ev;/* last PPS event id */
>> +unsigned int last_fetched_ev;/* last fetched PPS event id */
>> wait_queue_head_t queue;/* PPS event queue */
>>
>> unsigned int id;/* PPS source unique ID */
>
--
GNU/Linux Solutions e-mail: giometti@enneenne.com
Linux Device Driver giometti@linux.it
Embedded Systems phone: +39 349 2432127
UNIX programming
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: Re: [PATCH] pps: fix poll support
2025-04-10 7:42 ` Denis OSTERLAND-HEIM
@ 2025-04-10 7:57 ` Greg Kroah-Hartman
0 siblings, 0 replies; 4+ messages in thread
From: Greg Kroah-Hartman @ 2025-04-10 7:57 UTC (permalink / raw)
To: Denis OSTERLAND-HEIM
Cc: Andrew Morton, linux-kernel, stable, Rodolfo Giometti
On Thu, Apr 10, 2025 at 07:42:32AM +0000, Denis OSTERLAND-HEIM wrote:
> Before printing, think about environmental responsibility.This message may contain confidential information. If you are not authorized to receive this information please advise the sender immediately by reply e-mail and delete this message without making any copies. Any form of unauthorized use, publication, reproduction, copying or disclosure of the e-mail is not permitted. Information about data protection can be found on our homepage<https://www.diehl.com/metering/en/data-protection/>.
Now deleted.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-04-03 6:06 Re: [PATCH] pps: fix poll support Denis OSTERLAND-HEIM
2025-04-03 7:49 ` Rodolfo Giometti
2025-04-10 7:42 ` Denis OSTERLAND-HEIM
2025-04-10 7:57 ` Greg Kroah-Hartman
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