Re: [PATCH V2] wlcore: sdio: Fixup power on/off sequence

Ulf Hansson [off-list ref] writes:

On Wed, 16 Jan 2019 at 16:43, Tony Lindgren [off-list ref] wrote:

quoted

* Ulf Hansson [off-list ref] [190116 11:37]:

quoted

During "wlan-up", we are programming the FW into the WiFi-chip. However,
re-programming the FW doesn't work, unless a power cycle of the WiFi-chip
is made in-between the programmings.

To conform to this requirement and to fix the regression in a simple way,
let's start by allowing that the SDIO card (WiFi-chip) may stay powered on
(runtime resumed) when wl12xx_sdio_power_off() returns. The intent with the
current code is to treat this scenario as an error, but unfortunate this
doesn't work as expected, so let's fix this.

The other part is to guarantee that a power cycle of the SDIO card has been
completed when wl12xx_sdio_power_on() returns, as to allow the FW
programming to succeed. However, relying solely on runtime PM to deal with
this isn't sufficient. For example, userspace may prevent runtime suspend
via sysfs for the device that represents the SDIO card, leading to that the
mmc core also keeps it powered on. For this reason, let's instead do a
brute force power cycle in wl12xx_sdio_power_on().

Fixes: 728a9dc61f13 ("wlcore: sdio: Fix flakey SDIO runtime PM handling")
Signed-off-by: Ulf Hansson <redacted>
---

Changes in v2:
      - Keep the SDIO host claimed when calling mmc_hw_reset().
      - Add a fixes tag.

This v2 version works for me as tested with:

# while [ 1 ]; do ifconfig wlan0 down; ifconfig wlan0 up; done
[  181.364990] wlcore: down
[  182.116424] wlcore: firmware booted (Rev 6.3.10.0.141)
[  182.151641] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
[  182.166778] wlcore: down
[  182.773132] wlcore: firmware booted (Rev 6.3.10.0.141)
[  182.811096] IPv6: ADDRCONF(NETDEV_UP): wlan0: link is not ready
...

Thanks for fixing this issue properly, and feel free to add:

Tested-by: Tony Lindgren <tony@atomide.com>

Thanks for testing, great news!

Before queuing this as fix, let's also see what the Hikey folkz thinks
of this. I have pinged Anders and he is currently running a test
suite.

Kalle, can you please tag this for stable as well?

Ok, I'll queue this for 5.0 (but wait for testing feedback at least a
day) and add:

Cc: <redacted>

-- 
Kalle Valo