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a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1624430589; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=TlGZRZ99uCIt4JDAjOFXnswm4yaCa3ZMTl87RK83waE=; b=hrob67bWMmViAg5CAyhvDg8xtRHrAUBAM0VSFniEqSI0myWGdc/UaBO6QCSVllrliNsDjF D7AeOlonnA0UfzBQ== Received: from director2.suse.de ([192.168.254.72]) by imap3-int with ESMTPSA id RGKAHfzX0mBnawAALh3uQQ (envelope-from ); Wed, 23 Jun 2021 06:43:08 +0000 To: Liviu Dudau Cc: daniel@ffwll.ch, airlied@linux.ie, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, james.qian.wang@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, thierry.reding@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, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-mediatek@lists.infradead.org, nouveau@lists.freedesktop.org, linux-rockchip@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, linux-sunxi@lists.linux.dev, linux-tegra@vger.kernel.org References: <20210622141002.11590-1-tzimmermann@suse.de> <20210622141002.11590-5-tzimmermann@suse.de> <20210622152504.2sw6khajwydsoaqa@e110455-lin.cambridge.arm.com> From: Thomas Zimmermann Subject: Re: [PATCH v2 04/22] drm: Don't test for IRQ support in VBLANK ioctls Message-ID: Date: Wed, 23 Jun 2021 08:43:07 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.11.0 X-Mailing-List: linux-sunxi@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20210622152504.2sw6khajwydsoaqa@e110455-lin.cambridge.arm.com> Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="7jLGShJWLlf8CSqVlOcnyBWWcy9Lp6Rkb" This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --7jLGShJWLlf8CSqVlOcnyBWWcy9Lp6Rkb Content-Type: multipart/mixed; boundary="3ihYu1sFcNnMMAMmUEcEMG76YaQ22m49E"; protected-headers="v1" From: Thomas Zimmermann To: Liviu Dudau Cc: daniel@ffwll.ch, airlied@linux.ie, alexander.deucher@amd.com, christian.koenig@amd.com, Xinhui.Pan@amd.com, james.qian.wang@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, thierry.reding@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, amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-mediatek@lists.infradead.org, nouveau@lists.freedesktop.org, linux-rockchip@lists.infradead.org, linux-stm32@st-md-mailman.stormreply.com, linux-sunxi@lists.linux.dev, linux-tegra@vger.kernel.org Message-ID: Subject: Re: [PATCH v2 04/22] drm: Don't test for IRQ support in VBLANK ioctls References: <20210622141002.11590-1-tzimmermann@suse.de> <20210622141002.11590-5-tzimmermann@suse.de> <20210622152504.2sw6khajwydsoaqa@e110455-lin.cambridge.arm.com> In-Reply-To: <20210622152504.2sw6khajwydsoaqa@e110455-lin.cambridge.arm.com> --3ihYu1sFcNnMMAMmUEcEMG76YaQ22m49E Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: quoted-printable Hi Liviu Am 22.06.21 um 17:25 schrieb Liviu Dudau: > Hello, >=20 > On Tue, Jun 22, 2021 at 04:09:44PM +0200, Thomas Zimmermann wrote: >> For KMS drivers, replace the IRQ check in VBLANK ioctls with a check f= or >> vblank support. IRQs might be enabled wthout vblanking being supported= =2E >> >> This change also removes the DRM framework's only dependency on IRQ st= ate >> for non-legacy drivers. For legacy drivers with userspace modesetting,= >> the original test remains in drm_wait_vblank_ioctl(). >> >> v2: >> * keep the old test for legacy drivers in >> drm_wait_vblank_ioctl() (Daniel) >> >> Signed-off-by: Thomas Zimmermann >> --- >> drivers/gpu/drm/drm_irq.c | 10 +++------- >> drivers/gpu/drm/drm_vblank.c | 13 +++++++++---- >> 2 files changed, 12 insertions(+), 11 deletions(-) >> >> diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c >> index c3bd664ea733..1d7785721323 100644 >> --- a/drivers/gpu/drm/drm_irq.c >> +++ b/drivers/gpu/drm/drm_irq.c >> @@ -74,10 +74,8 @@ >> * only supports devices with a single interrupt on the main device = stored in >> * &drm_device.dev and set as the device paramter in drm_dev_alloc()= =2E >> * >> - * These IRQ helpers are strictly optional. Drivers which roll their = own only >> - * need to set &drm_device.irq_enabled to signal the DRM core that vb= lank >> - * interrupts are working. Since these helpers don't automatically cl= ean up the >> - * requested interrupt like e.g. devm_request_irq() they're not reall= y >> + * These IRQ helpers are strictly optional. Since these helpers don't= automatically >> + * clean up the requested interrupt like e.g. devm_request_irq() they= 're not really >> * recommended. >> */ >> =20 >> @@ -91,9 +89,7 @@ >> * and after the installation. >> * >> * This is the simplified helper interface provided for drivers with= no special >> - * needs. Drivers which need to install interrupt handlers for multip= le >> - * interrupts must instead set &drm_device.irq_enabled to signal the = DRM core >> - * that vblank interrupts are available. >> + * needs. >> * >> * @irq must match the interrupt number that would be passed to requ= est_irq(), >> * if called directly instead of using this helper function. >> diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank= =2Ec >> index 3417e1ac7918..a98a4aad5037 100644 >> --- a/drivers/gpu/drm/drm_vblank.c >> +++ b/drivers/gpu/drm/drm_vblank.c >> @@ -1748,8 +1748,13 @@ int drm_wait_vblank_ioctl(struct drm_device *de= v, void *data, >> unsigned int pipe_index; >> unsigned int flags, pipe, high_pipe; >> =20 >> - if (!dev->irq_enabled) >> - return -EOPNOTSUPP; >> + if (drm_core_check_feature(dev, DRIVER_MODESET)) { >> + if (!drm_dev_has_vblank(dev)) >> + return -EOPNOTSUPP; >> + } else { >> + if (!dev->irq_enabled) >> + return -EOPNOTSUPP; >> + } >=20 > For a system call that is used quite a lot by userspace we have increas= ed the code size > in a noticeable way. Can we not cache it privately? I'm not quite sure that I understand your concern. The additionally=20 called functions are trivial one-liners; probably inlined anyway. However, irq_enabled is only relevant for legacy drivers and will=20 eventually disappear behind CONFIG_DRM_LEGACY. We can rewrite the test=20 like this: ifdef CONFIG_DRM_LEGACY if (unlikely(check_feature(dev, DRIVER_LEGACY))) { if (!irq_enabled) return; } else #endif { if (!has_vblank_support(dev)) return; } As CONFIG_DRM_LEGACY is most likely disabled on concurrent systems, we'd = get a single test for the modern drivers. If DRM_LEGACYis on, the=20 compiler at least knows that the else branch is preferred. Best regards Thomas --=20 Thomas Zimmermann Graphics Driver Developer SUSE Software Solutions Germany GmbH Maxfeldstr. 5, 90409 N=C3=BCrnberg, Germany (HRB 36809, AG N=C3=BCrnberg) Gesch=C3=A4ftsf=C3=BChrer: Felix Imend=C3=B6rffer --3ihYu1sFcNnMMAMmUEcEMG76YaQ22m49E-- --7jLGShJWLlf8CSqVlOcnyBWWcy9Lp6Rkb Content-Type: application/pgp-signature; name="OpenPGP_signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="OpenPGP_signature" -----BEGIN PGP SIGNATURE----- wsF5BAABCAAjFiEExndm/fpuMUdwYFFolh/E3EQov+AFAmDS1/sFAwAAAAAACgkQlh/E3EQov+DQ GBAAgLEWLgvBzCF5hV0mjIUdLsPzDOR+sZaMmkihftgMzVIfDXBMfZp4PON/h5XP/oa3S7zWw9+W RaNndoHIiRezAR4dnNcXern7ByoYb3kFLVlzcdpjZYvhitX8fUEanpR8nSXzouFAPuevtw8dNzr3 pyvXZCqqdXCmGz09Qrfc48j7bCYMgZ/b21GUHjKRGIC7JFkcSnGm2JopJOCsc9EiUD7tr0l7VfwS /H0ho3e9vLqI/p+1MdU/KMUjItmN71b2VEm8yp0KPceIEiCgsggBrW4np4kg8qoBrSVFNT+NDy1O weBoJYVfyPVT4UJXatHhqff7l9GUVWHtk2h2JfMrPIGj4qc15wiXUAiY9Goi5+z/9MgpJLl0TkXt GkxkK4Vdx1AdFMhNfE0PqmHjp1pOlLU/apueEhoeVslIwyatSi2cuTLKmRylHOzBYQhK9VsnS0Ip bLKBFuKu1QNELEqow7/6jmoneBg7LQwCtrFUZZ1juJfaHqCGttl8f4SleboXZe0fb8nPAgrQPItN TNb/u1tvc0hQhQ2DooSdMzvuCsM5qPlCi2ZLUwNNsj9uJo6rYJ49Xv7ay4pKE0TWQQN9MC+oyaa1 InbjRqUF5ubLt361DDxI0YuEq7FBhvcQ1dC0J4I/uKgXvATLllGtOvUzyK0ZAkiXQZ+UKkd0HRDx v9w= =aQqG -----END PGP SIGNATURE----- --7jLGShJWLlf8CSqVlOcnyBWWcy9Lp6Rkb--