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Subject: Re: [PATCH] misc: rtsx: do not setting OC_POWER_DOWN reg in
 rtsx_pci_init_ocp()
To:     Bjorn Helgaas <helgaas@kernel.org>
Cc:     ricky_wu@realtek.com, arnd@arndb.de, gregkh@linuxfoundation.org,
        bhelgaas@google.com, vaibhavgupta40@gmail.com,
        rui_feng@realsil.com.cn, kdlnx@doth.eu,
        linux-kernel@vger.kernel.org
References: <20200913164957.GA1190742@bjorn-Precision-5520>
From:   Chris Clayton <chris2553@googlemail.com>
Message-ID: <6bfbb0ae-fc7e-0aec-4dab-24a3f3ba1168@googlemail.com>
Date:   Mon, 14 Sep 2020 08:55:29 +0100
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Thanks Bjorn.

On 13/09/2020 17:49, Bjorn Helgaas wrote:
> On Sun, Sep 13, 2020 at 09:40:56AM +0100, Chris Clayton wrote:
>> Hi Greg and Arnd,
>>
>> On 24/08/2020 04:00, ricky_wu@realtek.com wrote:
>>> From: Ricky Wu <ricky_wu@realtek.com>
>>>
>>> this power saving action in rtsx_pci_init_ocp() cause INTEL-NUC6 platform
>>> missing card reader
>>
>> In his changelog above, Ricky didn't mention that this patch fixes a
>> regression that was introduced (in 5.1) by commit bede03a579b3.
>>
>> The patch that I posted to LKML contained the appropriate Fixes, etc
>> tags. After discussion, the patch was changed to remove the code
>> that effectively disables the RTS5229 cardreader on (at least some)
>> Intel NUC boxes. I prepared the patch that Ricky submitted but he
>> didn't include my Signed-off-by or the Fixes tag. I think the
>> following needs to be added to the changelog.
>>
>> Fixes: bede03a579b3 ("misc: rtsx: Enable OCP for rts522a rts524a rts525a rts5260")
>> Link: https://marc.info/?l=linux-kernel&m=159105912832257
> 
> Better lore link:
> 
>   Link: https://lore.kernel.org/r/CACYmiSer8FA+qjh8NHZJ2maxSd-=RwDdZ2F7_-E4uM1NXuZ8gQ@mail.gmail.com/
> 
> But I'm not sure the above is the most relevant.  Seems like the one
> below is more to the point since it has the exact patch below and is
> part of a thread developing it:
> 
>   Link: https://lore.kernel.org/r/20da8b4b-8426-9568-c0f1-4d1c2006c53f@googlemail.com/
> 

Yes, I meant to change the quote to that thread but ... more haste less speed.

>> Link: https://bugzilla.kernel.org/show_bug.cgi?id=204003
>> Signed-off-by: Chris Clayton <chris2553@googlemail.com>
>>
>> bede03a579b3 introduced a bug which leaves the rts5229 PCI Express
>> card reader on the Intel NUC6CAYH box.
>>
>> My main point, however, is that the patch is also needed in the 5.4
>> (longterm) and 5.8 (stable) series kernels.
> 
> This would be accomplished by:
> 
> Cc: stable@vger.kernel.org	# v5.1+
> 

Thanks for the tip.

I'm about to set off on a 4-day journey, so I'll send an updated patch when I return on Friday,


>>> Signed-off-by: Ricky Wu <ricky_wu@realtek.com>
>>> ---
>>>  drivers/misc/cardreader/rtsx_pcr.c | 4 ----
>>>  1 file changed, 4 deletions(-)
>>>
>>> diff --git a/drivers/misc/cardreader/rtsx_pcr.c b/drivers/misc/cardreader/rtsx_pcr.c
>>> index 37ccc67f4914..3a4a7b0cc098 100644
>>> --- a/drivers/misc/cardreader/rtsx_pcr.c
>>> +++ b/drivers/misc/cardreader/rtsx_pcr.c
>>> @@ -1155,10 +1155,6 @@ void rtsx_pci_init_ocp(struct rtsx_pcr *pcr)
>>>  			rtsx_pci_write_register(pcr, REG_OCPGLITCH,
>>>  				SD_OCP_GLITCH_MASK, pcr->hw_param.ocp_glitch);
>>>  			rtsx_pci_enable_ocp(pcr);
>>> -		} else {
>>> -			/* OC power down */
>>> -			rtsx_pci_write_register(pcr, FPDCTL, OC_POWER_DOWN,
>>> -				OC_POWER_DOWN);
>>>  		}
>>>  	}
>>>  }
>>>