From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH v2] ahci: imx: Handle increased read failures for IMX53 temperature sensor in low frequency mode. Date: Mon, 13 Nov 2017 12:18:02 -0800 Message-ID: <20171113201802.GO983427@devbig577.frc2.facebook.com> References: <1510569061-28993-1-git-send-email-martyn.welch@collabora.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-qt0-f177.google.com ([209.85.216.177]:48227 "EHLO mail-qt0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755502AbdKMUSF (ORCPT ); Mon, 13 Nov 2017 15:18:05 -0500 Content-Disposition: inline In-Reply-To: <1510569061-28993-1-git-send-email-martyn.welch@collabora.co.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Martyn Welch Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, Egor Starkov On Mon, Nov 13, 2017 at 10:31:01AM +0000, Martyn Welch wrote: > From: Egor Starkov > > Extended testing has shown that the imx ahci driver sometimes requires > more than the 100 attempts currently alotted in the driver to perform a > successful temperature reading when running at minimum (throttled) CPU > frequency. > > Debugging suggests that the read cycle can take 160 attempts (which given > that the driver averages 80 readings from the ADC equates to one failure > on each read). > > Increase the attempt limit to 200 in order to greatly reduce the > likelihood of the driver failing to perform a temperature reading, > especially at low CPU frequency. > > Signed-off-by: Egor Starkov > Signed-off-by: Martyn Welch Applied to libata/for-4.15. Thanks. -- tejun