Re: [PATCH] ath10k: reset chip after supported check

From: Ben Greear <greearb@candelatech.com>
To: "Michał Kazior" <kazikcz@gmail.com>
Cc: "Arend Van Spriel" <arend.vanspriel@broadcom.com>,
	"Christian Lamparter" <chunkeey@gmail.com>,
	"Tomislav Požega" <pozega.tomislav@gmail.com>,
	linux-wireless <linux-wireless@vger.kernel.org>,
	openwrt-devel@lists.openwrt.org,
	"Kalle Valo" <kvalo@codeaurora.org>
Subject: Re: [PATCH] ath10k: reset chip after supported check
Date: Mon, 25 Mar 2019 13:22:58 -0700	[thread overview]
Message-ID: <f3763b33-7944-81f8-98e1-053e51474a38@candelatech.com> (raw)
In-Reply-To: <CABvG-CWP4y4MU1pJB8ZSpLPPYMkQ+=kQt1zRoUJW=0dMLbD5WQ@mail.gmail.com>

On 3/25/19 1:08 PM, Michał Kazior wrote:
> On Mon, 25 Mar 2019 at 16:55, Ben Greear <greearb@candelatech.com> wrote:
>> On 3/25/19 5:14 AM, Michał Kazior wrote:
>>> On Sat, 23 Mar 2019 at 08:20, Arend Van Spriel
>>> <arend.vanspriel@broadcom.com> wrote:
>>>>
>>>> * resending with corrected email address from Kalle
>>>> --------------------------------------------------------------------
>>>> + Michał
>>>
>>> Thanks!
>>>
>>>
>>>> On 3/22/2019 8:25 PM, Christian Lamparter wrote:
>>>>    > On Friday, March 22, 2019 7:58:40 PM CET Tomislav Požega wrote:
>>>>    >> When chip reset is done before the chip is checked if supported
>>>>    >> there will be crash. Previous behaviour caused bootloops on
>>>>    >> Archer C7 v1 units, this patch allows clean device boot without
>>>>    >> excluding ath10k driver.
>>>
>>> Can you elaborate more a bit? What kind of crashes are you seeing?
>>> What does the bootloop look like? Do you have uart connected to
>>> diagnose?
>>>
>>> Didn't C7 v1 have the old QCA9880 hw v1 which isn't really supported
>>> by ath10k? I recall the v1 chip was really buggy and required
>>> hammering registers sometimes to get things working.
>>
>> The crash is related to the v1 chip.  Is there a good way to detect
>> that this is the chip in question and only apply this work-around
>> for the problem chip?
> 
> I don't know of any good way to do that.
> 
> You could consider device-tree but that would be no different from
> having a module blacklist in the C7v1 build recipe, or to not build
> the module at all. That is unless you actually want to make v1 chip
> work with ath10k at which point there's more fun to be had before it
> can actually work.

I remember v1, and I have no interest in trying to make it work :)

If we could blacklist certain pci slots in the ath10k driver, I guess
that would work?

I think the goal is to not use the v1 chip, but allow users to add a
v2 NIC to the platform, so driver still needs to load.

Thanks,
Ben

-- 
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc  http://www.candelatech.com