91 lines
3.3 KiB
Diff
91 lines
3.3 KiB
Diff
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From 0442aa45f3365bad75d0ce862e7db3143cf9e1de Mon Sep 17 00:00:00 2001
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From: Samuel Holland <samuel@sholland.org>
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Date: Sat, 3 Apr 2021 16:47:11 -0500
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Subject: [PATCH 412/478] PM / devfreq: Do not require devices to have OPPs
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Since commit ea572f816032 ("PM / devfreq: Change return type of
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devfreq_set_freq_table()"), all devfreq devices are required to have a
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valid freq_table. If freq_table is not provided by the driver, it will
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be filled in by set_freq_table() from the OPPs; if that fails,
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devfreq_add_device() will return an error.
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However, since commit ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when
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adding the devfreq device"), devfreq devices are _also_ required to have
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an OPP table, even if they provide freq_table. devfreq_add_device()
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requires dev_pm_opp_find_freq_ceil() and dev_pm_opp_find_freq_floor() to
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return successfully, specifically to initialize scaling_min/max_freq.
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Not all drivers need an OPP table. For example, a driver where all
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frequencies are determined dynamically could work by filling out only
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freq_table. But with the current code it must call dev_pm_opp_add() on
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every freq_table entry to probe successfully.
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The offending properties, scaling_min/max_freq, are only necessary if a
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device has OPPs; if no OPPs exist at all, OPPs cannot be dynamically
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enabled or disabled, so those values have no effect. Thus it is trivial
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to restore support for devices with freq_table only and not OPPs -- move
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those initializations behind the check for a valid OPP table.
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Since get_freq_range() uses scaling_max_freq in a min() expression, it
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must be initialized to the maximum possible value. scaling_min_freq is
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initialized as well for consistency.
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Fixes: ab8f58ad72c4 ("PM / devfreq: Set min/max_freq when adding the devfreq device")
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Signed-off-by: Samuel Holland <samuel@sholland.org>
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---
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drivers/devfreq/devfreq.c | 36 ++++++++++++++++++++----------------
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1 file changed, 20 insertions(+), 16 deletions(-)
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diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
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index 06333d430382..dea2fab64dc7 100644
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--- a/drivers/devfreq/devfreq.c
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+++ b/drivers/devfreq/devfreq.c
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@@ -835,24 +835,28 @@ struct devfreq *devfreq_add_device(struct device *dev,
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mutex_lock(&devfreq->lock);
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}
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- devfreq->scaling_min_freq = find_available_min_freq(devfreq);
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- if (!devfreq->scaling_min_freq) {
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- mutex_unlock(&devfreq->lock);
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- err = -EINVAL;
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- goto err_dev;
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- }
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-
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- devfreq->scaling_max_freq = find_available_max_freq(devfreq);
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- if (!devfreq->scaling_max_freq) {
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- mutex_unlock(&devfreq->lock);
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- err = -EINVAL;
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- goto err_dev;
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- }
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-
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- devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
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devfreq->opp_table = dev_pm_opp_get_opp_table(dev);
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- if (IS_ERR(devfreq->opp_table))
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+ if (IS_ERR(devfreq->opp_table)) {
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devfreq->opp_table = NULL;
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+ devfreq->scaling_min_freq = 0;
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+ devfreq->scaling_max_freq = ULONG_MAX;
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+ } else {
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+ devfreq->scaling_min_freq = find_available_min_freq(devfreq);
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+ if (!devfreq->scaling_min_freq) {
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+ mutex_unlock(&devfreq->lock);
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+ err = -EINVAL;
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+ goto err_dev;
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+ }
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+
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+ devfreq->scaling_max_freq = find_available_max_freq(devfreq);
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+ if (!devfreq->scaling_max_freq) {
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+ mutex_unlock(&devfreq->lock);
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+ err = -EINVAL;
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+ goto err_dev;
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+ }
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+
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+ devfreq->suspend_freq = dev_pm_opp_get_suspend_opp_freq(dev);
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+ }
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atomic_set(&devfreq->suspend_count, 0);
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--
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2.35.3
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