From: "Heiko Stübner" <heiko@sntech.de>
To: Douglas Anderson <dianders@chromium.org>
Cc: John Youn <John.Youn@synopsys.com>,
balbi@ti.com, Wu Liang Feng <wulf@rock-chips.com>,
Yunzhi Li <lyz@rock-chips.com>,
linux-rockchip@lists.infradead.org,
Julius Werner <jwerner@chromium.org>,
johnyoun@synopsys.com, gregkh@linuxfoundation.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] usb: dwc2: host: Fix ahbcfg for rk3066
Date: Sat, 24 Oct 2015 15:08:05 +0200 [thread overview]
Message-ID: <1788167.5hyLBzbcrl@diego> (raw)
In-Reply-To: <1445384033-17050-1-git-send-email-dianders@chromium.org>
Am Dienstag, 20. Oktober 2015, 16:33:53 schrieb Douglas Anderson:
> The comment for ahbcfg for rk3066 parameters (also used for rk3288)
> claimed that ahbcfg was INCR16, but it wasn't. Since the bits weren't
> shifted properly, the 0x7 ended up being masked and we ended up
> programming 0x3 for the HBstLen. Let's set it to INCR16 properly.
>
> As per Wu Liang Feng at Rockchip this may increase transmission
> efficiency. I did blackbox tests with writing 0s to a USB-based SD
> reader (forcefully capping CPU Freq to try to measure efficiency):
> cd /sys/devices/system/cpu/cpu0/cpufreq
> echo userspace > scaling_governor
> echo 126000 > scaling_setspeed
> for i in $(seq 10); do
> dd if=/dev/zero of=/dev/sdb bs=1M count=750
> done
>
> With the above tests I found that speeds went from ~15MB/s to ~18MB/s.
> Note that most other tests I did (including reading from the same USB
> reader) didn't show any difference in performance.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
I gave this a spin on a rk3288-firefly, runs fine and doesn't have any
negative effects, so
Tested-by: Heiko Stuebner <heiko@sntech.de>
next prev parent reply other threads:[~2015-10-24 13:08 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-20 23:33 [PATCH] usb: dwc2: host: Fix ahbcfg for rk3066 Douglas Anderson
2015-10-24 13:08 ` Heiko Stübner [this message]
2015-10-26 22:57 ` John Youn
2015-10-30 8:08 ` Liangfeng Wu
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