From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752012AbbJXNIP (ORCPT ); Sat, 24 Oct 2015 09:08:15 -0400 Received: from gloria.sntech.de ([95.129.55.99]:41015 "EHLO gloria.sntech.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750762AbbJXNIN (ORCPT ); Sat, 24 Oct 2015 09:08:13 -0400 From: Heiko =?ISO-8859-1?Q?St=FCbner?= To: Douglas Anderson Cc: John Youn , balbi@ti.com, Wu Liang Feng , Yunzhi Li , linux-rockchip@lists.infradead.org, Julius Werner , 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 Message-ID: <1788167.5hyLBzbcrl@diego> User-Agent: KMail/4.14.10 (Linux/4.2.0-1-amd64; KDE/4.14.12; x86_64; ; ) In-Reply-To: <1445384033-17050-1-git-send-email-dianders@chromium.org> References: <1445384033-17050-1-git-send-email-dianders@chromium.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@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