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: e37440e7e2c2 ("OPP: Call dev_pm_opp_set_opp() for required OPPs") Cc: stable@vger.kernel.org Signed-off-by: Ulf Hansson ulf.hansson@linaro.org ---

Changes in v3: - Clarified the commitmsg.

Changes in v2: - Clarified the commitmsg. - Addressed some comments from Viresh. - Drop calls to _add_opp_dev() for required_devs.

--- drivers/opp/core.c | 56 ++++++++++++++++++---------------------------- 1 file changed, 22 insertions(+), 34 deletions(-)

diff --git a/drivers/opp/core.c b/drivers/opp/core.c index 5f4598246a87..494f8860220d 100644 --- a/drivers/opp/core.c +++ b/drivers/opp/core.c @@ -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++;