From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH] ARM: dts: am57xx-idk: Remove support for voltage switching for SD card Date: Thu, 2 May 2019 07:35:25 -0700 Message-ID: <20190502143525.GP8007@atomide.com> References: <20190502084748.22518-1-faiz_abbas@ti.com> <20190502142016.GO8007@atomide.com> <50559611-a501-4331-c88b-5d05f6e756e9@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <50559611-a501-4331-c88b-5d05f6e756e9@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: Faiz Abbas Cc: Faiz Abbas , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-omap@vger.kernel.org, mark.rutland@arm.com, robh+dt@kernel.org, bcousson@baylibre.com, ulf.hansson@linaro.org, adrian.hunter@intel.com List-Id: devicetree@vger.kernel.org * Faiz Abbas [190502 14:30]: > Hi Tony, > > On 02/05/19 7:50 PM, Tony Lindgren wrote: > > * Faiz Abbas [190502 01:48]: > >> If UHS speed modes are enabled, a compatible SD card switches down to > >> 1.8V during enumeration. If after this a software reboot/crash takes > >> place and on-chip ROM tries to enumerate the SD card, the difference in > >> IO voltages (host @ 3.3V and card @ 1.8V) may end up damaging the card. > >> > >> The fix for this is to have support for power cycling the card in > >> hardware (with a PORz/soft-reset line causing a power cycle of the > >> card). Since am571x-, am572x- and am574x-idk don't have this > >> capability, disable voltage switching for these boards. > >> > >> The major effect of this is that the maximum supported speed > >> mode is now high speed(50 MHz) down from SDR104(200 MHz). > > > > This sounds a bit urgent, does it also need a stable tag or is > > it safe to apply against any earlier kernels? > > > > This should be good to apply on any previous releases. OK applying both your MMC patches into fixes today. Thanks, Tony