From: "Сергей Янович" <ynvich@gmail.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: Chris Ball <cjb@laptop.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Linus Walleij <linus.walleij@linaro.org>,
Jaehoon Chung <jh80.chung@samsung.com>,
Namjae Jeon <linkinjeon@gmail.com>,
linux-kernel@vger.kernel.org, linux-mmc@vger.kernel.org
Subject: Re: [PATCH v2] wait while adding MMC host to ensure root mounts
Date: Wed, 27 Mar 2013 16:28:31 +0400 [thread overview]
Message-ID: <CAL0eWdGjPKUUcm6mStAHgHKHLABmPw7nMwDhR8D5rbvg+DPzfQ@mail.gmail.com> (raw)
In-Reply-To: <CAPDyKFp27MUOjhydLXf92vN3cua=XcX4oTJnMGfOJPpBhtwM8Q@mail.gmail.com>
Hi Ulf,
On 27 March 2013 15:13, Ulf Hansson <ulf.hansson@linaro.org> wrote:
> Moreover, this patch will have bad impact on booting the kernel, since
> every host device that has scheduled a detect work from it's probe
> function will also wait for it to finish. Even if it is the boot
> device of not. If this is needed, I would prefer that a host cap is
> used.
Do you have any profiling data supporting bad impact on boot?
It should be it in the range of dozens us, if any. Without the patch,
approx. 30% of boots succeeded with CONFIG_PREEMT and aprox. 95%
without CONFIG_PREEMT. mmc_rescan is just a few instructions, if there
is no card present. On boot and with a card present, it might only
sleep in the host implementation.
Anyway, something had to be done about mmc boot. rootdelay will not
report error if the card is absent or its partition table is damaged.
rootdelay is a workaround by definition, so it may occasionally fail
if it is too small. Big rootdealy has a clear bad impact on boot time.
next prev parent reply other threads:[~2013-03-27 12:28 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-14 1:06 [PATCH] wait while adding MMC host to ensure root mounts Sergey Yanovich
2013-03-14 1:23 ` [PATCH v2] " Sergey Yanovich
2013-03-14 4:08 ` Namjae Jeon
2013-03-14 11:57 ` Sergey Yanovich
2013-03-15 2:51 ` Jaehoon Chung
2013-03-22 17:03 ` Chris Ball
2013-03-27 11:13 ` Ulf Hansson
2013-03-27 11:57 ` Chris Ball
2013-04-02 13:36 ` Adrian Hunter
2013-04-02 14:24 ` Sergey Yanovich
2013-04-04 6:35 ` Adrian Hunter
2013-04-04 10:59 ` Sergey Yanovich
2013-04-04 11:35 ` Adrian Hunter
2013-04-04 12:32 ` Sergey Yanovich
2013-04-13 10:49 ` Sergey Yanovich
2013-04-13 12:52 ` Chris Ball
[not found] ` <CAPDyKFrF8pmo7mfa_1Vi2n=JBFd1h+VULQ1hJB75=DmNx0erdw@mail.gmail.com>
2013-04-13 12:52 ` Sergey Yanovich
2013-03-27 12:28 ` Сергей Янович [this message]
2013-04-02 10:13 ` Ulf Hansson
2013-04-02 10:35 ` Sergey Yanovich
2013-04-02 17:45 ` Ulf Hansson
2013-04-02 18:56 ` Sergey Yanovich
2013-03-14 2:47 ` [PATCH] " Greg Kroah-Hartman
2013-03-14 10:28 ` Sergey Yanovich
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