From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933455AbcFGV6Y (ORCPT ); Tue, 7 Jun 2016 17:58:24 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:35297 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933345AbcFGV6U (ORCPT ); Tue, 7 Jun 2016 17:58:20 -0400 MIME-Version: 1.0 In-Reply-To: <20160607135702.GA19771@griffinp-ThinkPad-X1-Carbon-2nd> References: <1465304543-23988-1-git-send-email-peter.griffin@linaro.org> <20160607133839.GH18047@dell> <20160607135702.GA19771@griffinp-ThinkPad-X1-Carbon-2nd> From: Ulf Hansson Date: Tue, 7 Jun 2016 23:58:17 +0200 Message-ID: Subject: Re: [PATCH] mmc: core: Fix mmc_select_hs200() regression in v4.7-rc. To: Peter Griffin , Lee Jones Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , kernel@stlinux.com, Adrian Hunter , linux-mmc , Arnd Bergmann Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7 June 2016 at 15:57, Peter Griffin wrote: > Hi Lee, > > On Tue, 07 Jun 2016, Lee Jones wrote: > >> On Tue, 07 Jun 2016, Peter Griffin wrote: >> >> > mmc_select_bus_width() returns bus width (4 or 8) on success or >> > zero if unsupported. If bus width is set successfully we then wish >> > to switch to HS200 mode. >> > >> > This avoids the following error message in v4.70-rc2 >> > >> > [ 2.523674] mmc0: mmc_select_hs200 failed, error 3 >> > [ 2.528516] mmc0: error 3 whilst initialising MMC card >> > >> > With this patch card is enumerated correctly >> > >> > [ 2.468065] mmc0: new HS200 MMC card at address 0001 >> > [ 2.468335] mmcblk0: mmc0:0001 P1XXXX 7.20 GiB >> > [ 2.468441] mmcblk0boot0: mmc0:0001 P1XXXX partition 1 2.00 MiB >> > [ 2.468552] mmcblk0boot1: mmc0:0001 P1XXXX partition 2 2.00 MiB >> > [ 2.468651] mmcblk0rpmb: mmc0:0001 P1XXXX partition 3 128 KiB >> > [ 2.469269] mmcblk0: p1 >> > >> > Fixes: 287980e (remove lots of IS_ERR_VALUE abuses) >> > Signed-off-by: Peter Griffin >> > Cc: Arnd Bergmann >> > --- >> > drivers/mmc/core/mmc.c | 4 ++-- >> > 1 file changed, 2 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c >> > index c984321..aafb73d 100644 >> > --- a/drivers/mmc/core/mmc.c >> > +++ b/drivers/mmc/core/mmc.c >> > @@ -1276,7 +1276,7 @@ static int mmc_select_hs200(struct mmc_card *card) >> > * switch to HS200 mode if bus width is set successfully. >> > */ >> > err = mmc_select_bus_width(card); >> > - if (!err) { >> > + if (err > 0) { >> > val = EXT_CSD_TIMING_HS200 | >> > card->drive_strength << EXT_CSD_DRV_STR_SHIFT; >> > err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL, >> > @@ -1583,7 +1583,7 @@ static int mmc_init_card(struct mmc_host *host, u32 ocr, >> > } else if (mmc_card_hs(card)) { >> > /* Select the desired bus width optionally */ >> > err = mmc_select_bus_width(card); >> > - if (!err) { >> > + if (err > 0) { >> > err = mmc_select_hs_ddr(card); >> > if (err) >> > goto free_card; >> >> Looks like this has already been 'fixed' in -rc2. > > Ah, it seems I was on -rc1, not -rc2 > >> >> Although, this patch does not work for me. >> mmc: fix mmc mode selection for HS-DDR and higher >> >> When IS_ERR_VALUE was removed from the mmc core code, it was replaced >> with a simple not-zero check. This does not work, as the value checked >> is the return value for mmc_select_bus_width, which returns the set >> bit width on success. This made eMMC modes higher than HS-DDR unusable. >> >> Fix this by checking for a positive return value instead. >> >> Fixes: 287980e49ffc ("remove lots of IS_ERR_VALUE abuses") >> Cc: Arnd Bergmann >> Signed-off-by: Chen-Yu Tsai >> Acked-by: Hans de Goede >> Reviewed-by: Krzysztof Kozlowski >> Acked-by: Jaehoon Chung >> Reviewed-by: Shawn Lin >> Tested-by: Marcel Ziswiler >> Tested-by: Bjorn Andersson >> Signed-off-by: Ulf Hansson >> >> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c >> index c984321..5d438ad 100644 >> --- a/drivers/mmc/core/mmc.c >> +++ b/drivers/mmc/core/mmc.c >> @@ -1276,7 +1276,7 @@ static int mmc_select_hs200(struct mmc_card *card) >> * switch to HS200 mode if bus width is set successfully. >> */ >> err = mmc_select_bus_width(card); >> - if (!err) { >> + if (err >= 0) { > > > This patch looks wrong to me, as if zero is returned by mmc_select_bus_width() it > means setting the bus width failed, and you most likely don't want to switch to > hs200 mode. > > Ulf - what is your opinion? > > regards, > > Peter.> The commit above (mmc: fix mmc mode selection for HS-DDR and higher), simply restored the old behaviour and that was sufficient to solve the regressions. Nevertheless I agree, that if mmc_select_bus_width() returns 0, that should likely mean that we shouldn't try to switch to hs200. If we want to change that, let's do that in a separate patch on top. So, do you see a problem in rc2? Kind regards Uffe