From mboxrd@z Thu Jan 1 00:00:00 1970 From: Heiko =?ISO-8859-1?Q?St=FCbner?= Subject: Re: [PATCH] usb: dwc2: host: Fix ahbcfg for rk3066 Date: Sat, 24 Oct 2015 15:08:05 +0200 Message-ID: <1788167.5hyLBzbcrl@diego> References: <1445384033-17050-1-git-send-email-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1445384033-17050-1-git-send-email-dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-rockchip" Errors-To: linux-rockchip-bounces+glpar-linux-rockchip=m.gmane.org-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org To: Douglas Anderson Cc: johnyoun-HKixBCOQz3hWk0Htik3J/w@public.gmane.org, gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, balbi-l0cyMroinI0@public.gmane.org, John Youn , linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Yunzhi Li , Julius Werner , Wu Liang Feng List-Id: linux-rockchip.vger.kernel.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 I gave this a spin on a rk3288-firefly, runs fine and doesn't have any negative effects, so Tested-by: Heiko Stuebner