Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <1589875163-3367-1-git-send-email-rui_feng@realsil.com.cn>
 <20200522091646.GA1201234@kroah.com> <CAK8P3a3Uk_fmJ3UA1nuChHLC6w3p_wZfkqqRLvB01W0uLEE3-w@mail.gmail.com>
 <2A308283684ECD4B896628E09AF5361E59ACF600@RS-MBS01.realsil.com.cn>
In-Reply-To: <2A308283684ECD4B896628E09AF5361E59ACF600@RS-MBS01.realsil.com.cn>
From:   Arnd Bergmann <arnd@arndb.de>
Date:   Mon, 25 May 2020 11:36:17 +0200
Message-ID: <CAK8P3a13P0NuogaQtvSAZRbJb5OaccVxegvqKpynWO65Ye3iKA@mail.gmail.com>
Subject: Re: [PATCH] [V2] mmc: rtsx: Add SD Express mode support for RTS5261
To:     =?UTF-8?B?5Yav6ZSQ?= <rui_feng@realsil.com.cn>
Cc:     Greg KH <gregkh@linuxfoundation.org>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 8BIT
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Mon, May 25, 2020 at 8:58 AM 冯锐 <rui_feng@realsil.com.cn> wrote:
> > On Fri, May 22, 2020 at 11:16 AM Greg KH <gregkh@linuxfoundation.org> wrote:
> > >
> > > If I can get an ack from the MMC maintainer, I can take this in my
> > > tree...
> > >
> > > {hint}
> >
> > I think this feature needs much more discussion to make sure we get a good
> > user experience when it gets added to all mmc controllers.
> >
> Only RTS5261 is affected by this patch. Other vendor's reader won't be affected.

That sounds like another problem with this patch:

The transition should probably be handled by the MMC core checking whether
the kernel, the mmc host and and the card all support SD express mode, and
then start the transition as well as falling back to SD mode if it doesn't come
up properly.

         Arnd