On 10/5/2022 11:38 PM, Miroslav Lichvar wrote:
> Some ancient kernels had a bug in reading of the clock frequency, which
> was worked around by commit da347d7a36f2 ("ptp4l: Set clock frequency on
> start").
Is it worth spelling out what kernel version this was fixed in?
>
> Drop this workaround and support for the old kernels to make
> clockadj_get_freq() useful.
>
> Signed-off-by: Miroslav Lichvar <mlich...@redhat.com>
> ---
> clock.c | 7 -------
> phc2sys.c | 4 ----
> ts2phc.c | 7 -------
> 3 files changed, 18 deletions(-)
>
> diff --git a/clock.c b/clock.c
> index d37bb87..46ac9c2 100644
> --- a/clock.c
> +++ b/clock.c
> @@ -1144,12 +1144,6 @@ struct clock *clock_create(enum clock_type type,
> struct config *config,
>
> if (c->clkid != CLOCK_INVALID) {
> fadj = (int) clockadj_get_freq(c->clkid);
> - /* Due to a bug in older kernels, the reading may silently fail
> - and return 0. Set the frequency back to make sure fadj is
> - the actual frequency of the clock. */
> - if (!c->free_running) {
> - clockadj_set_freq(c->clkid, fadj);
> - }
> /* Disable write phase mode if not implemented by driver */
> if (c->write_phase_mode && !phc_has_writephase(c->clkid)) {
> pr_err("clock does not support write phase mode");
> @@ -1755,7 +1749,6 @@ int clock_switch_phc(struct clock *c, int phc_index)
> return -1;
> }
> fadj = (int) clockadj_get_freq(clkid);
> - clockadj_set_freq(clkid, fadj);
> servo = servo_create(c->config, c->servo_type, -fadj, max_adj, 0);
> if (!servo) {
> pr_err("Switching PHC, failed to create clock servo");
> diff --git a/phc2sys.c b/phc2sys.c
> index 8d2624f..ebc43e5 100644
> --- a/phc2sys.c
> +++ b/phc2sys.c
> @@ -128,10 +128,6 @@ static struct servo *servo_add(struct phc2sys_private
> *priv,
>
> clockadj_init(clock->clkid);
> ppb = clockadj_get_freq(clock->clkid);
> - /* The reading may silently fail and return 0, reset the frequency to
> - make sure ppb is the actual frequency of the clock. */
> - if (!priv->free_running)
> - clockadj_set_freq(clock->clkid, ppb);
> if (clock->clkid == CLOCK_REALTIME) {
> sysclk_set_leap(0);
> max_ppb = sysclk_max_freq();
> diff --git a/ts2phc.c b/ts2phc.c
> index f7a57e4..f345370 100644
> --- a/ts2phc.c
> +++ b/ts2phc.c
> @@ -129,13 +129,6 @@ static struct servo *ts2phc_servo_create(struct
> ts2phc_private *priv,
> int fadj, max_adj;
>
> fadj = (int) clockadj_get_freq(clock->clkid);
> - /* Due to a bug in older kernels, the reading may silently fail
> - * and return 0. Set the frequency back to make sure fadj is
> - * the actual frequency of the clock.
> - */
> - if (!clock->no_adj) {
> - clockadj_set_freq(clock->clkid, fadj);
> - }
>
> max_adj = phc_max_adj(clock->clkid);
>
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