From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752202AbdKZM4U (ORCPT ); Sun, 26 Nov 2017 07:56:20 -0500 Received: from smtp.codeaurora.org ([198.145.29.96]:51358 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751950AbdKZM4R (ORCPT ); Sun, 26 Nov 2017 07:56:17 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 smtp.codeaurora.org 4709D67063 Authentication-Results: pdx-caf-mail.web.codeaurora.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: pdx-caf-mail.web.codeaurora.org; spf=none smtp.mailfrom=architt@codeaurora.org Subject: Re: [RFC][PATCH] drm: adv7511/33: Fix adv7511_cec_init() failure handling To: John Stultz , Arnd Bergmann Cc: Laurent Pinchart , David Airlie , Lars-Peter Clausen , Bhumika Goyal , Inki Dae , dri-devel@lists.freedesktop.org, lkml , Xinliang Liu , Dan Carpenter , Sean Paul , Hans Verkuil References: <1510873179-20786-1-git-send-email-john.stultz@linaro.org> From: Archit Taneja Message-ID: <6faf6790-c5a3-8ca7-eb51-115842a66ceb@codeaurora.org> Date: Sun, 26 Nov 2017 18:26:06 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.1 MIME-Version: 1.0 In-Reply-To: <1510873179-20786-1-git-send-email-john.stultz@linaro.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 11/17/2017 04:29 AM, John Stultz wrote: > From: Arnd Bergmann > > An otherwise correct cleanup patch from Dan Carpenter turned a broken > failure handling from a feature patch by Hans Verkuil into a kernel > Oops, so bisection points to commit 7af35b0addbc ("drm/kirin: Checking > for IS_ERR() instead of NULL") rather than 3b1b975003e4 ("drm: > adv7511/33: add HDMI CEC support"). > > I've managed to piece together several partial problems, though > I'm still struggling with the bigger picture: > > adv7511_probe() registers a drm_bridge structure that was allocated > with devm_kzalloc(). It calls adv7511_cec_init(), which fails for an > unknown reason, which in turn triggers the registered structure to be > removed. > > Elsewhere, kirin_drm_platform_probe() gets called, which calls > of_graph_get_remote_node(), and that returns NULL. Before Dan's > patch we would go on with a NULL pointer here and register that, > now kirin_drm_platform_probe() fails with -ENODEV. > > In a third driver, dsi_parse_dt() calls drm_of_find_panel_or_bridge(), > which after not finding a panel goes on to call of_drm_find_bridge(), > and that crashes due to the earlier list corruption. > > This addresses the first issue by making sure that adv7511_probe() > does not completely fail when the adv7511_cec_init() function fails, > and instead we just disable the CEC feature. This avoids having the > driver entirely fail to load if just the CEC initialization fails. > > Reported-by: Naresh Kamboju > Cc: Xinliang Liu > Cc: Dan Carpenter > Cc: Sean Paul > Cc: Hans Verkuil > Cc: Archit Taneja > Link: https://bugs.linaro.org/show_bug.cgi?id=3345 > Link: https://lkft.validation.linaro.org/scheduler/job/48017#L3551 > Fixes: 7af35b0addbc ("drm/kirin: Checking for IS_ERR() instead of NULL") > Fixes: 3b1b975003e4 ("drm: adv7511/33: add HDMI CEC support") > Signed-off-by: Arnd Bergmann > [jstultz: Reworked so when adv7511_cec_init() fails, we disable the feature instead > of disabling the entire driver, which causes graphics to not funciton] > Signed-off-by: John Stultz > --- > Just wanted to send out my rework of Arnd's patch here. > Feedback would be welcome. > > thanks > -john > > drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > index 0e14f15..939c3b9 100644 > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > @@ -1203,12 +1203,12 @@ static int adv7511_probe(struct i2c_client *i2c, const struct i2c_device_id *id) > > #ifdef CONFIG_DRM_I2C_ADV7511_CEC > ret = adv7511_cec_init(dev, adv7511, offset); > - if (ret) > - goto err_unregister_cec; > #else > - regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset, > - ADV7511_CEC_CTRL_POWER_DOWN); > + ret = 1; > #endif > + if (ret) > + regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset, > + ADV7511_CEC_CTRL_POWER_DOWN); This would force CEC to be powered off even if adv7511_cec_init() returned 0, right? We wouldn't want that if we want to use CEC on a platform that supports it. Do we know why the call to adv7511_cec_init() is failing on the Hikey board? If it's because there isn't a "cec" clock specified in DT, it's not really a fatal error, it just means that the platform hasn't been set up to support CEC. In that case, we should just power down the CEC block. So, if adv7511_cec_init() would return a -ENOENT, which we could use as a hint to power down CEC. So, maybe something like this?: #ifdef CONFIG_DRM_I2C_ADV7511_CEC ret = adv7511_cec_init(dev, adv7511, offset); if (ret && ret != -ENOENT) goto err_unregister_cec; #endif if (ret) regmap_write(adv7511->regmap, ADV7511_REG_CEC_CTRL + offset, ADV7511_CEC_CTRL_POWER_DOWN); Apart from this, we should also move adv7511_cec_init() up in the probe so that it's called before the drm_bridge is registered. Thanks, Archit > > return 0; > > -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project