linux-kernel - Re: PATCH: rtsx_pci driver - don't disable the rts5229 card reader on Intel NUC boxes

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Message-ID: <152ef6c0-f3c0-bb67-4175-adced3c720cd@googlemail.com>
Date:   Tue, 4 Aug 2020 12:51:41 +0100
From:   Chris Clayton <chris2553@...glemail.com>
To:     吳昊澄 Ricky <ricky_wu@...ltek.com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        "rdunlap@...radead.org" <rdunlap@...radead.org>,
        "philquadra@...il.com" <philquadra@...il.com>,
        Arnd Bergmann <arnd@...db.de>
Subject: Re: PATCH: rtsx_pci driver - don't disable the rts5229 card reader on
 Intel NUC boxes



On 04/08/2020 11:46, 吳昊澄 Ricky wrote:
>> -----Original Message-----
>> From: Chris Clayton [mailto:chris2553@...glemail.com]
>> Sent: Tuesday, August 04, 2020 4:51 PM
>> To: 吳昊澄 Ricky; gregkh@...uxfoundation.org
>> Cc: LKML; rdunlap@...radead.org; philquadra@...il.com; Arnd Bergmann
>> Subject: Re: PATCH: rtsx_pci driver - don't disable the rts5229 card reader on
>> Intel NUC boxes
>>
>>
>>
>> On 04/08/2020 09:08, 吳昊澄 Ricky wrote:
>>>> -----Original Message-----
>>>> From: gregkh@...uxfoundation.org [mailto:gregkh@...uxfoundation.org]
>>>> Sent: Tuesday, August 04, 2020 3:49 PM
>>>> To: 吳昊澄 Ricky
>>>> Cc: Chris Clayton; LKML; rdunlap@...radead.org; philquadra@...il.com;
>> Arnd
>>>> Bergmann
>>>> Subject: Re: PATCH: rtsx_pci driver - don't disable the rts5229 card reader on
>>>> Intel NUC boxes
>>>>
>>>> On Tue, Aug 04, 2020 at 02:44:41AM +0000, 吳昊澄 Ricky wrote:
>>>>> Hi Chris,
>>>>>
>>>>> rtsx_pci_write_register(pcr, FPDTL, OC_POWER_DOWN,
>> OC_POWER_DOWN);
>>>>> This register operation saved power under 1mA, so if do not care the 1mA
>>>> power we can have a patch to remove it, make compatible with NUC6
>>>>> We tested others our card reader that remove it, we did not see any side
>> effect
>>>>>
>>>>> Hi Greg k-h,
>>>>>
>>>>> Do you have any comments?
>>>>
>>>> comments on what?  I don't know what you are responding to here, sorry.
>>>>
>>> Can we have a patch to kernel for NUC6? It may cause more power(1mA) but it
>> will have more compatibility
>>>
>>
>> Ricky,
>>
>> I don't understand why you want to completely remove the code that sets up the
>> 1mA power saving. That code was there
>> even before your patch (bede03a579b3b4a036003c4862cc1baa4ddc351f), so I
>> assume it benefits some of the Realtek card
>> readers. Before your patch however, rtsx_pci_init_ocp() was not called for the
>> rts5229 reader, but the patch introduced
>> an unconditional call to that function into rtsx_pci_init_hw(), which is run for the
>> rts5229. That is what now disables
>> the card reader.
>>
>> Now, I don't know whether other cards are affected, although I don't recall
>> seeing any reported as I searched the kernel
>> and ubuntu bugzillas for any analysis of the problem. I know this is not what the
>> patch I sent does, but having thought
>> about it more, seems to me that the simplest fix is to skip the new call to
>> rtsx_pci_init_ocp() if the reader is an rts5229.
>>
> 
> Because we are thinking about if others our card reader that not belong A series(my ocp patch coverage) also on NUC6 platform maybe have the same problem... 
>  

OK. What if we do make the new call but only for the card readers that are in the A series? Are they the ones that have
PID_5nnn defines in include/linux/rtsx_pci.h? Or is there another simple way of identifying that a reader is a member of
the A series?

I'm thinking of something like:
static bool rtsx_pci_is_series_A(pcr)
{
	unsigned short device = pcr->pci->device;

	return device == PID524A || device == PID_5249 || device == PID_5250 || device == PID_525A
			|| device == PID_525A || device == PID_5260 || device == PID_5261;
}

then in rtsx_pci_init_hw() change the unconditional call to:

	if rtsx_pci_is_series_A(pcr)
		rtsx_pci_init_ocp();

Does that seem OK?

>> If you agree, I can prepare a patch and send it to you. Whatever the solution is, it
>> will also be needed in the stable
>> kernels later than 5.0.
>>
> 
> OK, I agree your opinion, for now can only patch rts5229 first make NUC6 user can work well
> 
> Thank you 
> 
>> Chris
>>>> greg k-h
>>>>
>>>> ------Please consider the environment before printing this e-mail.