From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757132AbeDZWQs (ORCPT ); Thu, 26 Apr 2018 18:16:48 -0400 Received: from perceval.ideasonboard.com ([213.167.242.64]:60952 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754760AbeDZWQq (ORCPT ); Thu, 26 Apr 2018 18:16:46 -0400 From: Laurent Pinchart To: Jia-Ju Bai Cc: architt@codeaurora.org, a.hajda@samsung.com, airlied@linux.ie, daniel.vetter@ffwll.ch, bhumirks@gmail.com, narmstrong@baylibre.com, inki.dae@samsung.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] gpu: drm: bridge: adv7511: Replace mdelay with usleep_range in adv7511_probe Date: Fri, 27 Apr 2018 01:16:59 +0300 Message-ID: <5009396.5p49gfLLAe@avalon> Organization: Ideas on Board Oy In-Reply-To: <1523435622-4329-1-git-send-email-baijiaju1990@gmail.com> References: <1523435622-4329-1-git-send-email-baijiaju1990@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Jia-Ju, Thank you for the patch. On Wednesday, 11 April 2018 11:33:42 EEST Jia-Ju Bai wrote: > adv7511_probe() is never called in atomic context. > This function is only set as ".probe" in struct i2c_driver. > > Despite never getting called from atomic context, adv7511_probe() > calls mdelay() to busily wait. > This is not necessary and can be replaced with usleep_range() to > avoid busy waiting. > > This is found by a static analysis tool named DCNS written by myself. > And I also manually check it. Nice work ! Is the tool open-source ? > Signed-off-by: Jia-Ju Bai > --- > drivers/gpu/drm/bridge/adv7511/adv7511_drv.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c index b2431ae..2cf7fa1 > 100644 > --- a/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > +++ b/drivers/gpu/drm/bridge/adv7511/adv7511_drv.c > @@ -1054,7 +1054,7 @@ static int adv7511_probe(struct i2c_client *i2c, const > struct i2c_device_id *id) } > > if (adv7511->gpio_pd) { > - mdelay(5); > + usleep_range(5000, 6000); > gpiod_set_value_cansleep(adv7511->gpio_pd, 0); > } The patch looks good to me. Reviewed-by: Laurent Pinchart -- Regards, Laurent Pinchart