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OPP: Fix support for required OPPs for multiple PM domains

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It has turned out that having _set_required_opps() to recursively call
dev_pm_opp_set_opp() to set the required OPPs, doesn't really work as well
as we expected.

More precisely, at each recursive call to dev_pm_opp_set_opp() we are
changing an OPP for a required_dev that belongs to a required-OPP table.
The problem with this, is that we may have several devices sharing the same
required-OPP table, which leads to an incorrect behaviour in regards to
aggregating the per device votes.

To fix the problem for a required-OPP table belonging to a PM domain, which
is the only existing usecase for now, let's simply replace the call to
dev_pm_opp_set_opp() in _set_required_opps() by a call to _set_opp_level().

Moving forward we may potentially need to add support for other types of
required-OPP tables. In this case, the aggregation needs to be thought of.

Fixes: e37440e7e2 ("OPP: Call dev_pm_opp_set_opp() for required OPPs")
Cc: stable@vger.kernel.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Link: https://lore.kernel.org/r/20240822224547.385095-2-ulf.hansson@linaro.org
This commit is contained in:
Ulf Hansson 2024-08-23 00:45:38 +02:00
parent 52dd070c62
commit 9ec87c5957
1 changed files with 22 additions and 34 deletions
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56
drivers/opp/core.c
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@ -1061,6 +1061,27 @@ static int _set_opp_bw(const struct opp_table *opp_table,
return 0;
}
static int _set_opp_level(struct device *dev, struct dev_pm_opp *opp)
{
unsigned int level = 0;
int ret = 0;
if (opp) {
if (opp->level == OPP_LEVEL_UNSET)
return 0;
level = opp->level;
}
/* Request a new performance state through the device's PM domain. */
ret = dev_pm_domain_set_performance_state(dev, level);
if (ret)
dev_err(dev, "Failed to set performance state %u (%d)\n", level,
ret);
return ret;
}
/* This is only called for PM domain for now */
static int _set_required_opps(struct device *dev, struct opp_table *opp_table,
struct dev_pm_opp *opp, bool up)
@ -1091,7 +1112,7 @@ static int _set_required_opps(struct device *dev, struct opp_table *opp_table,
if (devs[index]) {
required_opp = opp ? opp->required_opps[index] : NULL;
ret = dev_pm_opp_set_opp(devs[index], required_opp);
ret = _set_opp_level(devs[index], required_opp);
if (ret)
return ret;
}
@ -1102,27 +1123,6 @@ static int _set_required_opps(struct device *dev, struct opp_table *opp_table,
return 0;
}
static int _set_opp_level(struct device *dev, struct dev_pm_opp *opp)
{
unsigned int level = 0;
int ret = 0;
if (opp) {
if (opp->level == OPP_LEVEL_UNSET)
return 0;
level = opp->level;
}
/* Request a new performance state through the device's PM domain. */
ret = dev_pm_domain_set_performance_state(dev, level);
if (ret)
dev_err(dev, "Failed to set performance state %u (%d)\n", level,
ret);
return ret;
}
static void _find_current_opp(struct device *dev, struct opp_table *opp_table)
{
struct dev_pm_opp *opp = ERR_PTR(-ENODEV);
@ -2457,18 +2457,6 @@ static int _opp_attach_genpd(struct opp_table *opp_table, struct device *dev,
}
}
/*
* Add the virtual genpd device as a user of the OPP table, so
* we can call dev_pm_opp_set_opp() on it directly.
*
* This will be automatically removed when the OPP table is
* removed, don't need to handle that here.
*/
if (!_add_opp_dev(virt_dev, opp_table->required_opp_tables[index])) {
ret = -ENOMEM;
goto err;
}
opp_table->required_devs[index] = virt_dev;
index++;
name++;