Re: [PATCH 2/2] opp: Manage empty OPP tables with clk handle

From: Rajendra Nayak
Date: Wed Jul 03 2019 - 06:47:22 EST




On 7/3/2019 3:17 PM, Viresh Kumar wrote:
On 03-07-19, 14:41, Rajendra Nayak wrote:
[]..

Explain the rationale behind this code here in a comment.

+ if (!_get_opp_count(opp_table)) {
+ ret = _generic_set_opp_clk_only(dev, clk, freq);
+ goto put_opp_table;
+ }
+
temp_freq = old_freq;
old_opp = _find_freq_ceil(opp_table, &temp_freq);
if (IS_ERR(old_opp)) {

Also, rebase over the OPP branch please:

thanks, I will fix/rebase and repost,
in the meantime while I was testing this a little more I realized I also need
something like the change below to avoid a refcount mismatch WARN when empty OPP
table is removed using dev_pm_opp_of_remove_table()

diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index fa7d4d6d37b3..20128a88baf2 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -2118,7 +2118,8 @@ void _dev_pm_opp_find_and_remove_table(struct device *dev)
return;
}
- _put_opp_list_kref(opp_table);
+ if (_get_opp_count(opp_table))
+ _put_opp_list_kref(opp_table);
/* Drop reference taken by _find_opp_table() */
dev_pm_opp_put_opp_table(opp_table);

Does this look like a good way to fix it?

No. If an OPP table only has dynamic OPPs, this will still generate
warning. Below is the fix I would suggest. Please test it, I haven't
tested it at all :)

thanks, yes, this seems to work.

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