From: Dirk Behme <dirk.behme@de.bosch.com>
To: Chris Ball <cjb@laptop.org>
Cc: "linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
"linaro-dev@lists.linaro.org" <linaro-dev@lists.linaro.org>,
"linux-embedded@vger.kernel.org" <linux-embedded@vger.kernel.org>,
Jassi Brar <jaswinder.singh@linaro.org>
Subject: Re: [PATCH 1/2] mmc: block: mmcblkN: use slot index instead of dynamic name index
Date: Wed, 8 Aug 2012 08:12:22 +0200 [thread overview]
Message-ID: <50220346.4030606@de.bosch.com> (raw)
In-Reply-To: <8739402g1m.fsf@octavius.laptop.org>
Hi Chris,
On 06.08.2012 17:31, Chris Ball wrote:
> Hi,
>
> On Mon, Aug 06 2012, Dirk Behme wrote:
>> On embedded devices, often there is a combination of removable mmc
>> devices (e.g. MMC/SD cards) and hard wired ones (e.g. eMMC).
>> Depending on the hardware configuration, the 'mmcblkN' node might
>> change if the removable device is available or not at boot time.
>>
>> E.g. if the removable device is attached at boot time, it might
>> become mmxblk0. And the hard wired one mmcblk1. But if the removable
>> device isn't there at boot time, the hard wired one will become
>> mmcblk0. This makes it somehow difficult to hard code the root device
>> to the non-removable device and boot fast.
>>
>> This change does simply associate 'N' of 'mmcblkN' with the slot index
>> instead of the dynamic name index. The slot index is always the same,
>> ensuring that the non-removable mmc device is associated always
>> with the same mmcblkN. Independent of the availability of the removable
>> one.
>
> I like this change in principle,
Thanks :)
> but doesn't it break boot for everyone
> currently using e.g. root=/dev/mmcblk0p1 on slot index 2? That doesn't
> sound like an acceptable regression.
I'm not really an expert of the code in block.c. Could you imagine a
change which has the same result we'd like to get with the proposed
patch but doesn't have the regression you mention?
Many thanks and best regards
Dirk
prev parent reply other threads:[~2012-08-08 6:12 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-06 7:24 [PATCH 1/2] mmc: block: mmcblkN: use slot index instead of dynamic name index Dirk Behme
[not found] ` <1344237900-14815-1-git-send-email-dirk.behme-V5te9oGctAVWk0Htik3J/w@public.gmane.org>
2012-08-06 7:25 ` [PATCH 2/2] mmc: block: remove unused name_idx Dirk Behme
2012-08-06 15:31 ` [PATCH 1/2] mmc: block: mmcblkN: use slot index instead of dynamic name index Chris Ball
2012-08-06 16:15 ` Jassi Brar
2012-08-08 6:12 ` Dirk Behme [this message]
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