diff mbox series

[iwl-net,v1,3/5] igc: Move ktime snapshot into PTM retry loop

Message ID 20240807003032.10300-4-christopher.s.hall@intel.com
State Changes Requested
Headers show
Series igc: PTM timeout fix | expand

Commit Message

Hall, Christopher S Aug. 7, 2024, 12:30 a.m. UTC
From: Christopher S M Hall <christopher.s.hall@intel.com>

Move ktime_get_snapshot() into the loop. If a retry does occur, a more
recent snapshot will result in a more accurate cross-timestamp.

Fixes: a90ec8483732 ("igc: Add support for PTP getcrosststamp()")
Signed-off-by: Christopher S M Hall <christopher.s.hall@intel.com>
---
 drivers/net/ethernet/intel/igc/igc_ptp.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

Comments

Corinna Vinschen Aug. 8, 2024, 2:54 p.m. UTC | #1
On Aug  6 17:30, christopher.s.hall@intel.com wrote:
> From: Christopher S M Hall <christopher.s.hall@intel.com>
> 
> Move ktime_get_snapshot() into the loop. If a retry does occur, a more
> recent snapshot will result in a more accurate cross-timestamp.
> 
> Fixes: a90ec8483732 ("igc: Add support for PTP getcrosststamp()")
> Signed-off-by: Christopher S M Hall <christopher.s.hall@intel.com>
> ---
>  drivers/net/ethernet/intel/igc/igc_ptp.c | 18 +++++++++---------
>  1 file changed, 9 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c
> index 00cc80d8d164..fb885fcaa97c 100644
> --- a/drivers/net/ethernet/intel/igc/igc_ptp.c
> +++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
> @@ -1011,16 +1011,16 @@ static int igc_phc_get_syncdevicetime(ktime_t *device,
>  	int err, count = 100;
>  	ktime_t t1, t2_curr;
>  
> -	/* Get a snapshot of system clocks to use as historic value. */
> -	ktime_get_snapshot(&adapter->snapshot);
> -
> +	/* Doing this in a loop because in the event of a
> +	 * badly timed (ha!) system clock adjustment, we may
> +	 * get PTM errors from the PCI root, but these errors
> +	 * are transitory. Repeating the process returns valid
> +	 * data eventually.
> +	 */
>  	do {
> -		/* Doing this in a loop because in the event of a
> -		 * badly timed (ha!) system clock adjustment, we may
> -		 * get PTM errors from the PCI root, but these errors
> -		 * are transitory. Repeating the process returns valid
> -		 * data eventually.
> -		 */
> +		/* Get a snapshot of system clocks to use as historic value. */
> +		ktime_get_snapshot(&adapter->snapshot);
> +
>  		igc_ptm_trigger(hw);
>  
>  		err = readx_poll_timeout(rd32, IGC_PTM_STAT, stat,
> -- 
> 2.34.1

Reviewed-by: Corinna Vinschen <vinschen@redhat.com>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/igc/igc_ptp.c b/drivers/net/ethernet/intel/igc/igc_ptp.c
index 00cc80d8d164..fb885fcaa97c 100644
--- a/drivers/net/ethernet/intel/igc/igc_ptp.c
+++ b/drivers/net/ethernet/intel/igc/igc_ptp.c
@@ -1011,16 +1011,16 @@  static int igc_phc_get_syncdevicetime(ktime_t *device,
 	int err, count = 100;
 	ktime_t t1, t2_curr;
 
-	/* Get a snapshot of system clocks to use as historic value. */
-	ktime_get_snapshot(&adapter->snapshot);
-
+	/* Doing this in a loop because in the event of a
+	 * badly timed (ha!) system clock adjustment, we may
+	 * get PTM errors from the PCI root, but these errors
+	 * are transitory. Repeating the process returns valid
+	 * data eventually.
+	 */
 	do {
-		/* Doing this in a loop because in the event of a
-		 * badly timed (ha!) system clock adjustment, we may
-		 * get PTM errors from the PCI root, but these errors
-		 * are transitory. Repeating the process returns valid
-		 * data eventually.
-		 */
+		/* Get a snapshot of system clocks to use as historic value. */
+		ktime_get_snapshot(&adapter->snapshot);
+
 		igc_ptm_trigger(hw);
 
 		err = readx_poll_timeout(rd32, IGC_PTM_STAT, stat,