From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753797AbbI3HyW (ORCPT ); Wed, 30 Sep 2015 03:54:22 -0400 Received: from lists.s-osg.org ([54.187.51.154]:40063 "EHLO lists.s-osg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751184AbbI3HyT (ORCPT ); Wed, 30 Sep 2015 03:54:19 -0400 Subject: Re: [PATCH] ARM: exynos_defconfig: Enable WiFi-Ex as a module instead built-in To: Krzysztof Kozlowski , linux-kernel@vger.kernel.org References: <1443530546-3066-1-git-send-email-javier@osg.samsung.com> <560B2EA4.8050406@samsung.com> <560B8DA3.6060507@osg.samsung.com> <560B9145.6070606@samsung.com> Cc: Mauro Carvalho Chehab , Kukjin Kim , Thierry Reding , Anand Moon , Russell King , linux-samsung-soc@vger.kernel.org, Andreas Faerber , Lukasz Majewski , linux-arm-kernel@lists.infradead.org From: Javier Martinez Canillas X-Enigmail-Draft-Status: N1110 Message-ID: <560B9525.8020808@osg.samsung.com> Date: Wed, 30 Sep 2015 09:54:13 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.0.1 MIME-Version: 1.0 In-Reply-To: <560B9145.6070606@samsung.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Krzysztof, On 09/30/2015 09:37 AM, Krzysztof Kozlowski wrote: > On 30.09.2015 16:22, Javier Martinez Canillas wrote: >> Hello Krzysztof, >> >> On 09/30/2015 02:36 AM, Krzysztof Kozlowski wrote: >>> On 29.09.2015 21:42, Javier Martinez Canillas wrote: >>>> The Marvell WiFi-Ex driver tries to load a firmware on probe. So if the >>>> driver is built-in and probed before a firmware is available, this is >>>> not loaded and the chip does not work. >>>> >>>> This happens for example if an initramfs isn't used since the driver is >>>> probed before the root filesystem is mounted. >>>> >>>> Change the default config since the driver isn't needed for machines to >>>> boot and is more convenient to have it enabled as a module to avoid >>>> requiring an initramfs or to have the firmware built into the kernel. >>>> >>>> Signed-off-by: Javier Martinez Canillas >>>> >>>> --- >>>> >>>> arch/arm/configs/exynos_defconfig | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> The user-space can always initiate re-probing of device - just re-bind >> >> It is true that you can force a re-probing from user-space by doing: >> >> $ echo "mmc2:0001:1" > /sys/bus/sdio/drivers/mwifiex_sdio/unbind >> $ echo "mmc2:0001:1" > /sys/bus/sdio/drivers/mwifiex_sdio/bind > > I suppose the unbind won't be needed, because device aborted the > probe... so only one another bind. > Right, only the bind is needed indeed since the device is unbind after the firmware loading fails. I just wanted to confirm that I understood what you said before correctly. >> >> but: >> >> a) This is not obvious. In fact, I didn't think that possibility >> before you mentioned and I've been using Linux for many years :) > > Eh, questionable. Obvious for me :) > Fair enough, maybe is just me then :) >> >> b) This is not something that isn't done automatically by init systems. > > Right. err, I wanted to say "is not something that is done automatically" but fortunately you understood what I meant. > >> >> So what users will see is that the driver was probed successfully but >> the firmware fails to load later (since the driver users the async >> request_firmware_nowait function to request the firmware). > > Okay. > >> >>> it. However I assume that driver cannot work without firmware? >>> >> >> Yes, it doesn't. I explained this in the commit message. Do you >> think it should be made more clear? > > No, its OK, I agree. > > Reviewed-by: Krzysztof Kozlowski > Great, thanks a lot for your feedback and review! > Best regards, > Krzysztof Best regards, -- Javier Martinez Canillas Open Source Group Samsung Research America