linux-kernel - Re: [PATCH v2 1/2] mmc: core: Let sanitize timeout readable/writable via sysfs

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Date:   Fri, 02 Apr 2021 09:01:37 +0200
From:   Bean Huo <huobean@...il.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     "Shimoda, Yoshihiro" <yoshihiro.shimoda.uh@...esas.com>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        linux-mmc <linux-mmc@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Bean Huo <beanhuo@...ron.com>
Subject: Re: [PATCH v2 1/2] mmc: core: Let sanitize timeout
 readable/writable via sysfs

On Fri, 2021-04-02 at 00:48 +0200, Ulf Hansson wrote:
> On Thu, 1 Apr 2021 at 15:29, Bean Huo <huobean@...il.com> wrote:
> 
> > From: Bean Huo <beanhuo@...ron.com>
> > As the density increases, the 4-minute timeout value for
> > sanitize is no longer feasible. At the same time, devices
> > of different densities have different timeout values, and it is
> > difficult to obtain a unified standard timeout value. Therefore,
> > it is better to let the user explicitly change  sanitize timeout
> > value according to the eMMC density on the board.
> 
> 
> This makes sense. The current timeout in the mmc core isn't good
> 
> enough. However, I think there is a better option than inventing a
> 
> sysfs node to allow userspace to specify the timeout.
> 
> 
> 
> First, we have the card quirks that the mmc core uses to allow us to
> 
> modify a common behaviour (in this case timeouts values for sanitize
> 
> operations). This can be used to enforce a specific timeout for the
> 
> eMMC card. I think this should take precedence over anything else.
> 
> 
> 
> Second, the ioctl command allows you to specify a specific command
> 
> timeout in the struct mmc_ioc_cmd (.cmd_timeout_ms). If this is
> 
> specified from user space we could forward it to mmc_santize() and
> use
> 
> that rather than the default MMC_SANITIZE_TIMEOUT_MS.
> 
> 
> 
> Would this satisfy your needs?
> 

Hi Ulf,
Add card quirk is diffcult since different card with different timeout.
I prefer to your second one. I will change this patch based on your
comments.

Thanks,
Bean

> 
> 
> Kind regards
> 
> Uffe