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

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Message-ID: <19de15c2f07d447dace6bea483d38159@realtek.com>
Date:   Tue, 4 Aug 2020 10:46:58 +0000
From:   吳昊澄 Ricky <ricky_wu@...ltek.com>
To:     Chris Clayton <chris2553@...glemail.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

> -----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... 
 
> 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.