On Fri, 21 Jul 2017, Dan Williams wrote:
On Fri, 2017-07-21 at 16:56 +0200, Rafal wrote:
I have a board with ap6212 chip and I have encountered two problems
with the brcmfmac driver operating with this device. First problem I
describe below, second one in separate mail.
Namely, I have noticed quite poor connection with the device despite
good signal strength. Ping to the device was very uneven, about 50 -
100 ms in average, 10 - 20% of packets loss. After some
investigations I have found that problem is caused by powersave
feature on wiphy (BRCMF_C_SET_PM command). When the value is set to
PM_OFF, the problem does not appear - ping is quite stable, ~2ms.
When set to PM_FAST, the ping is bad.
The brcmfmac driver currently does not have possibility to turn off
the powersave feature. I have added the possibility on 4.11.6 kernel
I don't think that's true? The driver implements the nl80211
set_power_mgmt hook, which lets you turn off powersave with 'iw'. That
seems like a much better option than a module parameter. I know other
drivers have the module parameter, but I personally consider that
legacy/holdover, given that we have runtime toggles for this kind of
thing.
brcmf_cfg80211_set_power_mgmt() should do what you need, right?
Yes, it does.
In fact, I needed only a parameter in OF database. This is a bug in the
device or firmware and I needed to disable the feature for this chip.
Many device drivers allow to specify in OF database that driver should
use a quirk. This is similar situation.
I have added the kernel parameter as an additional feature. I thought
that not all platforms are using devicetree database. But maybe it is a
bad idea.
Rafal
Dan
