From mboxrd@z Thu Jan 1 00:00:00 1970 From: Evgeniy Didin Subject: Re: [PATCH] mmc: dw_mmc: fix falling from idmac to PIO mode when dw_mci_reset occurs Date: Thu, 15 Mar 2018 17:24:09 +0000 Message-ID: <1521134649.10304.7.camel@synopsys.com> References: <20180314193051.16791-1-Evgeniy.Didin@synopsys.com> <1521119909.10304.1.camel@synopsys.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Language: en-US Content-ID: <054C4DB5CC0BE34EB46B16934AF59F33@internal.synopsys.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-snps-arc" Errors-To: linux-snps-arc-bounces+gla-linux-snps-arc=m.gmane.org@lists.infradead.org To: "ulf.hansson@linaro.org" , "Evgeniy.Didin@synopsys.com" Cc: "shawn.lin@rock-chips.com" , "Alexey.Brodkin@synopsys.com" , "linux-mmc@vger.kernel.org" , "Jisheng.Zhang@synaptics.com" , "jh80.chung@samsung.com" , "andy.shevchenko@gmail.com" , "linux-snps-arc@lists.infradead.org" , "Eugeniy.Paltsev@synopsys.com" List-Id: linux-mmc@vger.kernel.org On Thu, 2018-03-15 at 14:39 +0100, Ulf Hansson wrote: > On 15 March 2018 at 14:18, Evgeniy Didin wrote: > > Hello Ulf, > > > > On Thu, 2018-03-15 at 10:57 +0100, Ulf Hansson wrote: > > > On 14 March 2018 at 20:30, Evgeniy Didin wrote: > > > > It was found that in IDMAC mode after soft-reset driver switches > > > > to PIO mode. > > > > > > > > That's what happens in case of DTO timeout overflow calculation failure: > > > > 1. soft-reset is called > > > > 2. driver restarts dma > > > > 3. descriptors states are checked, one of descriptor is owned by the IDMAC. > > > > 4. driver can't use DMA and then switches to PIO mode. > > > > > > > > Failure was already fixed in: > > > > https://urldefense.proofpoint.com/v2/url?u=https-3A__www.spinics.net_lists_linux-2Dmmc_msg48125.html&d=DwIBaQ&c=DPL6_X_6JkXFx7AXWqB0tg&r=vQk-RIbjwN0zvlwiMSpq3LYUTNf7Gqc4ujh > > > > osYI > > > > TtAw&m=6rPWpKUYQD3kY-2OEikJUWyEJvwKJljWHFC8rd2TCak&s=JjX0Dx8-eSyW2cATMsnG1eAzrKgoDkS1bcS5XYrVtlE&e=. > > > > > > Evgeniy, > > > > > > It seems like I should squash this fix into the above commit? Makes sense? > > > > IMHO it is not a good idea, because this fix is orthogonal to the above commit. > > Debugging drto overflow issue we found this strange behavior. > > Okay! Thanks for clarifying. > > > This might be general issue of soft-reset. So I think this should be separate patch. > > Also if these patches are independent, it will be easier to backport them. > > Should I add a stable tag then? Sure. The issue can happen since v3.17, because starting with this version function dw_mci_reset was implemented. Commit 3a33a94ce270 ("mmc: dw_mmc: change to use recommended reset procedure"). Best regards, Evgeniy Didin