From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id AF816C43619 for ; Wed, 17 Mar 2021 10:05:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 89B4764F6B for ; Wed, 17 Mar 2021 10:05:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230378AbhCQKEi (ORCPT ); Wed, 17 Mar 2021 06:04:38 -0400 Received: from relay11.mail.gandi.net ([217.70.178.231]:37321 "EHLO relay11.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229549AbhCQKES (ORCPT ); Wed, 17 Mar 2021 06:04:18 -0400 Received: from uno.localdomain (host-79-22-58-175.retail.telecomitalia.it [79.22.58.175]) (Authenticated sender: jacopo@jmondi.org) by relay11.mail.gandi.net (Postfix) with ESMTPSA id BCE96100007; Wed, 17 Mar 2021 10:04:14 +0000 (UTC) Date: Wed, 17 Mar 2021 11:04:45 +0100 From: Jacopo Mondi To: Kieran Bingham Cc: Jacopo Mondi , laurent.pinchart+renesas@ideasonboard.com, niklas.soderlund+renesas@ragnatech.se, geert@linux-m68k.org, Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 12/18] media: i2c: rdacm21: Give more time to OV490 to boot Message-ID: <20210317100445.h3yqmrrnghq76mjb@uno.localdomain> References: <20210315131512.133720-1-jacopo+renesas@jmondi.org> <20210315131512.133720-13-jacopo+renesas@jmondi.org> <0826484e-8ae7-677e-6de2-8f019e9733fc@ideasonboard.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <0826484e-8ae7-677e-6de2-8f019e9733fc@ideasonboard.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Kieran, Laurent, On Mon, Mar 15, 2021 at 05:22:37PM +0000, Kieran Bingham wrote: > On 15/03/2021 13:15, Jacopo Mondi wrote: > > It has been observed through repeated testing (250 boots) that in the > > 10% of the cases the RDACM21 initialization sequence errors out due a > > timeout waiting for the OV490 firmware to complete its boot phase. > > > > Albeit being the current timeout relatively large (300-600 milliseconds), > > doubling it reduces the sporadic error rate down to 1 over an 80 boot > > sequences test run. > > > > The firmware boot delay is unfortunately not characterized in the camera > > module manual. > > > > I wonder if we could characterize this alone by pulling this down until > we see failures increase, with all the other fixes in place... > > I don't think that's required, but it might be something to check later > if we don't get rid of that 1/80 failure. This is actually driving me crazy :/ I had another test run with a surprising 10% failures. All the failures were due to the ov490 firmware boot I'm trying to mitigate here. I went up to give it -6 seconds- and I still get failures in the same percentage. Another run of 20 boots gave 30% failures with the delay I have here in this patch. Just to make sure I was not going crazy I reduced the delay to 1msec and I get an 80% failure rate. Still, I've seen the 1 on 80 failures (I swear! I have logs! :) I've checked what the BSP does, and if after some 300 attempts the ov490 doesn't boot, they simply go an reset it. https://github.com/renesas-rcar/linux-bsp/commit/0cf6e36f5bf49e1c2aab87139ec5b588623c56f8#diff-d770cad7d6f04923d9e89dfe7da369bb3006776d6e4fb8ef79353d5fab3cd25aR827 (sorry, I don't seem to be able to point you to the ov490.c#827 with an URL) I assume we don't want anything like this in an upstream driver, but I'm really running out of any plausible explanation :( > > > > > Fixes: a59f853b3b4b ("media: i2c: Add driver for RDACM21 camera module") > > Signed-off-by: Jacopo Mondi > > Reviewed-by: Kieran Bingham > > > --- > > drivers/media/i2c/rdacm21.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/drivers/media/i2c/rdacm21.c b/drivers/media/i2c/rdacm21.c > > index 50a9b0d8255d..07cf077d8efd 100644 > > --- a/drivers/media/i2c/rdacm21.c > > +++ b/drivers/media/i2c/rdacm21.c > > @@ -53,7 +53,7 @@ > > #define OV490_PID 0x8080300a > > #define OV490_VER 0x8080300b > > #define OV490_PID_TIMEOUT 20 > > -#define OV490_OUTPUT_EN_TIMEOUT 300 > > +#define OV490_OUTPUT_EN_TIMEOUT 600 > > > > #define OV490_GPIO0 BIT(0) > > #define OV490_SPWDN0 BIT(0) > > >