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=-9.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B608DC48BDF for ; Thu, 24 Jun 2021 12:37:06 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 5DD54613F6 for ; Thu, 24 Jun 2021 12:37:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5DD54613F6 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:Message-ID:Date:References :In-Reply-To:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=HRey48zQc69kytIBoc8C5yJUabaSBKFPcWqMcZfZIS8=; b=Nwd98R4eZEy/60 wAXzfSi7qaKqZxJBP1lHaQasT+iOqU+qqM9B156m5RdRO5Xphz0LCmgETqruutX8PGQ/O/AK1n8aM 4JCXZzNiv/nUQF68uolZWzd7uNqX+tMq6IrE8D3FhF8+RwmEbHkZHAS8Ou+jJQTV0WlQkyTmxpln+ LYcWFPsmE+GKJ517+O/roHlHGHbJ0e2fRn9WhZR06WSjuAcIl/mV4CKwsgqYyZ3AWXaE+fUZJnnfw Ip2c0c+95jj3j2ezZm+liIMKwTk7UbrlMEJw5t+F7zXcuKmco/OAVMfVyQTj8IhCafaF24nHS7PFR vjdD+NHotB4tZxekwBbA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lwObH-00EdKb-Lj; Thu, 24 Jun 2021 12:36:55 +0000 Received: from mga02.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1lwObE-00EdJm-K2; Thu, 24 Jun 2021 12:36:54 +0000 IronPort-SDR: RhlWFK7f6exWXaO108a6enm3yZiGobBkNDJJKEN+m+Bt6MJXLahe5Tg+JQ5W7f6yY1okUlcSPv PjJi7wk4mg6A== X-IronPort-AV: E=McAfee;i="6200,9189,10024"; a="194599218" X-IronPort-AV: E=Sophos;i="5.83,296,1616482800"; d="scan'208";a="194599218" Received: from orsmga001.jf.intel.com ([10.7.209.18]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2021 05:36:51 -0700 IronPort-SDR: 9KysYK/2HzWxqWorwm4RDCvD9fzYUECjO+Kr/55Zbl/DRmlbCimO4edKqAHIWPRoPcJqgJVxQB +d0WGJ9B4vNg== X-IronPort-AV: E=Sophos;i="5.83,296,1616482800"; d="scan'208";a="487740905" Received: from schulke-mobl1.ger.corp.intel.com (HELO localhost) ([10.252.59.242]) by orsmga001-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Jun 2021 05:36:27 -0700 From: Jani Nikula To: Thierry Reding , Thomas Zimmermann Cc: daniel@ffwll.ch, airlied@linux.ie, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, james.qian.wang@arm.com, liviu.dudau@arm.com, mihail.atanassov@arm.com, brian.starkey@arm.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, inki.dae@samsung.com, jy0922.shim@samsung.com, sw0312.kim@samsung.com, kyungmin.park@samsung.com, krzysztof.kozlowski@canonical.com, xinliang.liu@linaro.org, tiantao6@hisilicon.com, john.stultz@linaro.org, kong.kongxinwei@hisilicon.com, puck.chen@hisilicon.com, laurentiu.palcu@oss.nxp.com, l.stach@pengutronix.de, p.zabel@pengutronix.de, shawnguo@kernel.org, s.hauer@pengutronix.de, kernel@pengutronix.de, festevam@gmail.com, linux-imx@nxp.com, chunkuang.hu@kernel.org, matthias.bgg@gmail.com, bskeggs@redhat.com, tomba@kernel.org, hjc@rock-chips.com, heiko@sntech.de, benjamin.gaignard@linaro.org, yannick.fertre@foss.st.com, philippe.cornu@foss.st.com, mcoquelin.stm32@gmail.com, alexandre.torgue@foss.st.com, wens@csie.org, jernej.skrabec@gmail.com, jonathanh@nvidia.com, jyri.sarha@iki.fi, emma@anholt.net, linux-graphics-maintainer@vmware.com, zackr@vmware.com, hyun.kwon@xilinx.com, laurent.pinchart@ideasonboard.com, michal.simek@xilinx.com, rodrigo.vivi@intel.com, linux@armlinux.org.uk, kieran.bingham+renesas@ideasonboard.com, rodrigosiqueiramelo@gmail.com, melissa.srw@gmail.com, hamohammed.sa@gmail.com, linux-samsung-soc@vger.kernel.org, nouveau@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-stm32@st-md-mailman.stormreply.com, linux-rockchip@lists.infradead.org, linux-mediatek@lists.infradead.org, amd-gfx@lists.freedesktop.org, Daniel Vetter , linux-tegra@vger.kernel.org, linux-sunxi@lists.linux.dev, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH v3 04/27] drm: Don't test for IRQ support in VBLANK ioctls In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20210624072916.27703-1-tzimmermann@suse.de> <20210624072916.27703-5-tzimmermann@suse.de> <87im23u1ok.fsf@intel.com> <877dijtzl2.fsf@intel.com> Date: Thu, 24 Jun 2021 15:36:24 +0300 Message-ID: <87zgvfsalz.fsf@intel.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210624_053652_741405_6C118C32 X-CRM114-Status: GOOD ( 22.90 ) X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Thu, 24 Jun 2021, Thierry Reding wrote: > On Thu, Jun 24, 2021 at 11:07:57AM +0200, Thomas Zimmermann wrote: >> Hi >> >> Am 24.06.21 um 10:51 schrieb Jani Nikula: >> > On Thu, 24 Jun 2021, Thomas Zimmermann wrote: >> > > Hi >> > > >> > > Am 24.06.21 um 10:06 schrieb Jani Nikula: >> > > > On Thu, 24 Jun 2021, Thomas Zimmermann wrote: >> > > > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c >> > > > > index 3417e1ac7918..10fe16bafcb6 100644 >> > > > > --- a/drivers/gpu/drm/drm_vblank.c >> > > > > +++ b/drivers/gpu/drm/drm_vblank.c >> > > > > @@ -1748,8 +1748,16 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, >> > > > > unsigned int pipe_index; >> > > > > unsigned int flags, pipe, high_pipe; >> > > > > - if (!dev->irq_enabled) >> > > > > - return -EOPNOTSUPP; >> > > > > +#if defined(CONFIG_DRM_LEGACY) >> > > > > + if (unlikely(drm_core_check_feature(dev, DRIVER_LEGACY))) { >> > > > > + if (!dev->irq_enabled) >> > > > > + return -EOPNOTSUPP; >> > > > > + } else /* if DRIVER_MODESET */ >> > > > > +#endif >> > > > > + { >> > > > > + if (!drm_dev_has_vblank(dev)) >> > > > > + return -EOPNOTSUPP; >> > > > > + } >> > > > >> > > > Sheesh I hate this kind of inline #ifdefs. >> > > > >> > > > Two alternate suggestions that I believe should be as just efficient: >> > > >> > > Or how about: >> > > >> > > static bool drm_wait_vblank_supported(struct drm_device *dev) >> > > >> > > { >> > > >> > > if defined(CONFIG_DRM_LEGACY) >> > > if (unlikely(drm_core_check_feature(dev, DRIVER_LEGACY))) >> > > >> > > return dev->irq_enabled; >> > > >> > > #endif >> > > return drm_dev_has_vblank(dev); >> > > >> > > } >> > > >> > > >> > > ? >> > > >> > > It's inline, but still readable. >> > >> > It's definitely better than the original, but it's unclear to me why >> > you'd prefer this over option 2) below. I guess the only reason I can >> > think of is emphasizing the conditional compilation. However, >> > IS_ENABLED() is widely used in this manner specifically to avoid inline >> > #if, and the compiler optimizes it away. >> >> It's simply more readable to me as the condition is simpler. But option 2 is >> also ok. > > Perhaps do something like this, then: > > if (IS_ENABLED(CONFIG_DRM_LEGACY)) { > if (unlikely(drm_core_check_feature(dev, DRIVER_LEGACY))) > return dev->irq_enabled; > } > > return drm_dev_has_vblank(dev); > > That's about just as readable as the variant involving the preprocessor > but has all the benefits of not using the preprocessor. Looks like a winner to me. :) BR, Jani. -- Jani Nikula, Intel Open Source Graphics Center _______________________________________________ Linux-mediatek mailing list Linux-mediatek@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-mediatek