From mboxrd@z Thu Jan 1 00:00:00 1970 From: Seung-Woo Kim Subject: Re: drm: exynos: mixer: fix using usleep() in atomic context Date: Thu, 22 Jan 2015 16:47:25 +0900 Message-ID: <54C0AB0D.9090209@samsung.com> References: <1417307725-5975-1-git-send-email-tjakobi@math.uni-bielefeld.de> <1417307725-5975-2-git-send-email-tjakobi@math.uni-bielefeld.de> <20141201155447.GE11943@ulmo.nvidia.com> <7454d0630d95195d41c3906637e223af@math.uni-bielefeld.de> <20141217075433.GA2814@ulmo> <54C02C4F.4080307@math.uni-bielefeld.de> Reply-To: sw0312.kim@samsung.com Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from mailout3.samsung.com ([203.254.224.33]:10995 "EHLO mailout3.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750915AbbAVHrW (ORCPT ); Thu, 22 Jan 2015 02:47:22 -0500 Received: from epcpsbgr5.samsung.com (u145.gpu120.samsung.co.kr [203.254.230.145]) by mailout3.samsung.com (Oracle Communications Messaging Server 7u4-24.01 (7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0NIK005WPIYWWX60@mailout3.samsung.com> for linux-samsung-soc@vger.kernel.org; Thu, 22 Jan 2015 16:47:20 +0900 (KST) In-reply-to: <54C02C4F.4080307@math.uni-bielefeld.de> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Tobias Jakobi Cc: Inki Dae , Thierry Reding , linux-samsung-soc@vger.kernel.org, dri-devel@lists.freedesktop.org, Seung-Woo Kim Hello, On 2015=EB=85=84 01=EC=9B=94 22=EC=9D=BC 07:46, Tobias Jakobi wrote: > Hello! >=20 >=20 > Inki Dae wrote: >> The use of spin lock, reg_slock, has been used for a long time and w= e >> hadn't some cleanups to spin lock codes so far. The spin lock is als= o >> used in here and there of mixer driver. And at least, it seems that >> the use of spin lock isn't required in mixer_win_reset. I don't see >> any atomic contexts in mixer module except interrupt handler. >> >> To Seung-Woo, >> I know that you referred to mixer codes of v4l2 based mixer driver. = So >> was the spin lock used in origin v4l2 driver? or Is there any reason >> that you used the spin lock? The spinlock usage was originated from Tomasz Stanislawski's s5p-tv. >> >> Anyway, we will have some testing to check hdmi and mixer drivers >> without spin lock. So we will remove or replace it with mutex if >> needed. >> >> Thanks, >> Inki Dae >=20 > So it's some weeks later and as far as I can see there has been no > changes to the spinlock usage. Wouldn't it be better to apply this pa= tch > _now_ (since the use of 'usleep_range' is just plain wrong while unde= r > spinlock). When the spinlock setup gets cleaned up later, then we can > always change back to 'usleep_range' again. >=20 > Any thoughts? In s5p-tv, same patch is already applied by Tomasz, so I agree to apply this patch also. Best Regards, - Seung-Woo Kim >=20 > With best wishes, > Tobias >=20 > _______________________________________________ > dri-devel mailing list > dri-devel@lists.freedesktop.org > http://lists.freedesktop.org/mailman/listinfo/dri-devel >=20 --=20 Seung-Woo Kim Samsung Software R&D Center --