Re: [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to sdhci-iproc.c for MMC

From	Stephen Warren <swarren@wwwdotorg.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to sdhci-iproc.c for MMC
Date	2016-04-01 04:10 +0200
Message-ID	<riWH9-5RD-25@gated-at.bofh.it> (permalink)
References	<riV8m-4z1-7@gated-at.bofh.it> <riV8n-4z1-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 03/31/2016 06:28 PM, Eric Anholt wrote:
> This approximately triples write performance for the SD card.  My card
> is too full of important data to collect very reliable numbers, but I
> see 271.361% +/- 166.742% improvement (n=3 before, 6 after), for 'dd
> if=/dev/zero of=/boot/asdf bs=1M count=3 oflag=dsync,direct'.  Read
> performance appears to be unaffected.

I thought that switching the defconfig wasn't possible, since this HW 
module relies on the SoC core clock, and that can be asynchronously 
changed by the FW running on the VideoCore. Consequently, this change 
isn't safe unless the user puts non-default options in their config.txt.

The same comment applies to "[PATCH 1/4] ARM: bcm2835: Switch BCM2835 to 
sdhci-iproc.c for MMC" in the other series.

Thread

[PATCH 1/3] ARM: multi_v7_defconfig: Add more BCM2835 support Eric Anholt <eric@anholt.net> - 2016-04-01 02:30 +0200
  [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to sdhci-iproc.c for MMC Eric Anholt <eric@anholt.net> - 2016-04-01 02:30 +0200
    Re: [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to  sdhci-iproc.c for MMC Stephen Warren <swarren@wwwdotorg.org> - 2016-04-01 04:10 +0200
      Re: [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to sdhci-iproc.c for MMC Eric Anholt <eric@anholt.net> - 2016-04-01 17:50 +0200
      Re: [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to  sdhci-iproc.c for MMC Stephen Warren <swarren@wwwdotorg.org> - 2016-04-01 19:00 +0200
        Re: [PATCH 2/3] ARM: multi_v7_defconfig: Switch BCM2835 to  sdhci-iproc.c for MMC Stefan Wahren <stefan.wahren@i2se.com> - 2016-04-01 22:20 +0200
  Re: [PATCH 1/3] ARM: multi_v7_defconfig: Add more BCM2835 support Stephen Warren <swarren@wwwdotorg.org> - 2016-04-01 04:10 +0200

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