Subject: Re: [PATCH] ath10k: reset chip after supported check
To:     Christian Lamparter <chunkeey@gmail.com>,
        =?UTF-8?Q?Tomislav_Po=c5=beega?= <pozega.tomislav@gmail.com>
Cc:     linux-wireless@vger.kernel.org, openwrt-devel@lists.openwrt.org,
        kalle@codeaurora.org,
        =?UTF-8?Q?Micha=c5=82_Kazior?= <kazikcz@gmail.com>
References: <1553281120-22139-1-git-send-email-pozega.tomislav@gmail.com>
 <3337086.qEUs9xMCTV@debian64>
From:   Arend Van Spriel <arend.vanspriel@broadcom.com>
Message-ID: <fe853ec8-0dca-d931-8632-fbe4df5cfaf8@broadcom.com>
Date:   Sat, 23 Mar 2019 08:16:25 +0100
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+ Michał

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.
>>
> You need
> 
> Fixes: 1a7fecb766c8 ("ath10k: reset chip before reading chip_id in probe")
> 
> too

Looking at the commit subject makes me suspicious whether this is a 
proper fix.

>> Signed-off-by: Tomislav Požega <pozega.tomislav@gmail.com>
>> ---
>>   drivers/net/wireless/ath/ath10k/pci.c |   12 ++++++------
>>   1 files changed, 6 insertions(+), 6 deletions(-)
>>
>> diff --git a/drivers/net/wireless/ath/ath10k/pci.c b/drivers/net/wireless/ath/ath10k/pci.c
>> index e24403c..ec681da 100644
>> --- a/drivers/net/wireless/ath/ath10k/pci.c
>> +++ b/drivers/net/wireless/ath/ath10k/pci.c
>> @@ -3619,12 +3619,6 @@ static int ath10k_pci_probe(struct pci_dev *pdev,
>>   		goto err_deinit_irq;
>>   	}
>>   
>> -	ret = ath10k_pci_chip_reset(ar);
>> -	if (ret) {
>> -		ath10k_err(ar, "failed to reset chip: %d\n", ret);
>> -		goto err_free_irq;
>> -	}
>> -
>>   	bus_params.dev_type = ATH10K_DEV_TYPE_LL;
>>   	bus_params.link_can_suspend = true;
>>   	bus_params.chip_id = ath10k_pci_soc_read32(ar, SOC_CHIP_ID_ADDRESS);

It seems to me the chip reset was done explicitly *before* reading the 
chipid for a reason.

"""
ath10k: reset chip before reading chip_id in probe
There are some very rare cases with some hardware
configuration that the device doesn't init quickly
enough in which case reading chip_id yielded 0.
This caused driver to subsequently fail to setup
the device.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>
"""

Might be the ath10k_pci_chip_reset() function needs to be modified to 
work properly for Archer C7 v1 units.

Regards,
Arend