From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart 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> References: <1523435622-4329-1-git-send-email-baijiaju1990@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by gabe.freedesktop.org (Postfix) with ESMTPS id D448D6E603 for ; Thu, 26 Apr 2018 22:16:46 +0000 (UTC) In-Reply-To: <1523435622-4329-1-git-send-email-baijiaju1990@gmail.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Jia-Ju Bai Cc: narmstrong@baylibre.com, airlied@linux.ie, daniel.vetter@ffwll.ch, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, bhumirks@gmail.com List-Id: dri-devel@lists.freedesktop.org SGkgSmlhLUp1LAoKVGhhbmsgeW91IGZvciB0aGUgcGF0Y2guCgpPbiBXZWRuZXNkYXksIDExIEFw cmlsIDIwMTggMTE6MzM6NDIgRUVTVCBKaWEtSnUgQmFpIHdyb3RlOgo+IGFkdjc1MTFfcHJvYmUo KSBpcyBuZXZlciBjYWxsZWQgaW4gYXRvbWljIGNvbnRleHQuCj4gVGhpcyBmdW5jdGlvbiBpcyBv bmx5IHNldCBhcyAiLnByb2JlIiBpbiBzdHJ1Y3QgaTJjX2RyaXZlci4KPiAKPiBEZXNwaXRlIG5l dmVyIGdldHRpbmcgY2FsbGVkIGZyb20gYXRvbWljIGNvbnRleHQsIGFkdjc1MTFfcHJvYmUoKQo+ IGNhbGxzIG1kZWxheSgpIHRvIGJ1c2lseSB3YWl0Lgo+IFRoaXMgaXMgbm90IG5lY2Vzc2FyeSBh bmQgY2FuIGJlIHJlcGxhY2VkIHdpdGggdXNsZWVwX3JhbmdlKCkgdG8KPiBhdm9pZCBidXN5IHdh aXRpbmcuCj4gCj4gVGhpcyBpcyBmb3VuZCBieSBhIHN0YXRpYyBhbmFseXNpcyB0b29sIG5hbWVk IERDTlMgd3JpdHRlbiBieSBteXNlbGYuCj4gQW5kIEkgYWxzbyBtYW51YWxseSBjaGVjayBpdC4K Ck5pY2Ugd29yayAhIElzIHRoZSB0b29sIG9wZW4tc291cmNlID8KCj4gU2lnbmVkLW9mZi1ieTog SmlhLUp1IEJhaSA8YmFpamlhanUxOTkwQGdtYWlsLmNvbT4KPiAtLS0KPiAgZHJpdmVycy9ncHUv ZHJtL2JyaWRnZS9hZHY3NTExL2Fkdjc1MTFfZHJ2LmMgfCAyICstCj4gIDEgZmlsZSBjaGFuZ2Vk LCAxIGluc2VydGlvbigrKSwgMSBkZWxldGlvbigtKQo+IAo+IGRpZmYgLS1naXQgYS9kcml2ZXJz L2dwdS9kcm0vYnJpZGdlL2Fkdjc1MTEvYWR2NzUxMV9kcnYuYwo+IGIvZHJpdmVycy9ncHUvZHJt L2JyaWRnZS9hZHY3NTExL2Fkdjc1MTFfZHJ2LmMgaW5kZXggYjI0MzFhZS4uMmNmN2ZhMQo+IDEw MDY0NAo+IC0tLSBhL2RyaXZlcnMvZ3B1L2RybS9icmlkZ2UvYWR2NzUxMS9hZHY3NTExX2Rydi5j Cj4gKysrIGIvZHJpdmVycy9ncHUvZHJtL2JyaWRnZS9hZHY3NTExL2Fkdjc1MTFfZHJ2LmMKPiBA QCAtMTA1NCw3ICsxMDU0LDcgQEAgc3RhdGljIGludCBhZHY3NTExX3Byb2JlKHN0cnVjdCBpMmNf Y2xpZW50ICppMmMsIGNvbnN0Cj4gc3RydWN0IGkyY19kZXZpY2VfaWQgKmlkKSB9Cj4gCj4gIAlp ZiAoYWR2NzUxMS0+Z3Bpb19wZCkgewo+IC0JCW1kZWxheSg1KTsKPiArCQl1c2xlZXBfcmFuZ2Uo NTAwMCwgNjAwMCk7Cj4gIAkJZ3Bpb2Rfc2V0X3ZhbHVlX2NhbnNsZWVwKGFkdjc1MTEtPmdwaW9f cGQsIDApOwo+ICAJfQoKVGhlIHBhdGNoIGxvb2tzIGdvb2QgdG8gbWUuCgpSZXZpZXdlZC1ieTog TGF1cmVudCBQaW5jaGFydCA8bGF1cmVudC5waW5jaGFydEBpZGVhc29uYm9hcmQuY29tPgoKLS0g ClJlZ2FyZHMsCgpMYXVyZW50IFBpbmNoYXJ0CgoKCl9fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJpLWRldmVsQGxp c3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFu L2xpc3RpbmZvL2RyaS1kZXZlbAo= 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