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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4598AC433EF for ; Thu, 4 Nov 2021 17:57:41 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (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 1023E60D07 for ; Thu, 4 Nov 2021 17:57:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 1023E60D07 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=lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 87DA573723; Thu, 4 Nov 2021 17:57:40 +0000 (UTC) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by gabe.freedesktop.org (Postfix) with ESMTPS id CA84E73723; Thu, 4 Nov 2021 17:57:39 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10158"; a="232007463" X-IronPort-AV: E=Sophos;i="5.87,209,1631602800"; d="scan'208";a="232007463" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2021 10:57:39 -0700 X-IronPort-AV: E=Sophos;i="5.87,209,1631602800"; d="scan'208";a="501633554" Received: from mihaelac-mobl.ger.corp.intel.com (HELO localhost) ([10.249.32.21]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2021 10:57:31 -0700 From: Jani Nikula To: Sam Ravnborg , Javier Martinez Canillas In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20211104160707.1407052-1-javierm@redhat.com> <20211104160707.1407052-2-javierm@redhat.com> Date: Thu, 04 Nov 2021 19:57:29 +0200 Message-ID: <87r1bvajna.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Nouveau] [PATCH v2 1/2] drm: Add a drm_drv_enabled() to check if drivers should be enabled X-BeenThere: nouveau@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Nouveau development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: David Airlie , dri-devel@lists.freedesktop.org, Gurchetan Singh , Gerd Hoffmann , Dave Airlie , amd-gfx@lists.freedesktop.org, VMware Graphics , Peter Robinson , nouveau@lists.freedesktop.org, spice-devel@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, Ben Skeggs , Michel =?utf-8?Q?D=C3=A4nzer?= , Hans de Goede , Rodrigo Vivi , virtualization@lists.linux-foundation.org, Pekka Paalanen , "Pan, Xinhui" , linux-kernel@vger.kernel.org, Alex Deucher , Christian =?utf-8?Q?K=C3=B6nig?= Errors-To: nouveau-bounces@lists.freedesktop.org Sender: "Nouveau" On Thu, 04 Nov 2021, Sam Ravnborg wrote: > Hi Javier, > > On Thu, Nov 04, 2021 at 05:07:06PM +0100, Javier Martinez Canillas wrote: >> Some DRM drivers check the vgacon_text_force() function return value as an >> indication on whether they should be allowed to be enabled or not. >> >> This function returns true if the nomodeset kernel command line parameter >> was set. But there may be other conditions besides this to determine if a >> driver should be enabled. >> >> Let's add a drm_drv_enabled() helper function to encapsulate that logic so >> can be later extended if needed, without having to modify all the drivers. >> >> Also, while being there do some cleanup. The vgacon_text_force() function >> is guarded by CONFIG_VGA_CONSOLE and there's no need for callers to do it. >> >> Suggested-by: Thomas Zimmermann >> Signed-off-by: Javier Martinez Canillas >> --- >> >> diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c >> index 8214a0b1ab7f..3fb567d62881 100644 >> --- a/drivers/gpu/drm/drm_drv.c >> +++ b/drivers/gpu/drm/drm_drv.c >> @@ -975,6 +975,26 @@ int drm_dev_set_unique(struct drm_device *dev, const char *name) >> } >> EXPORT_SYMBOL(drm_dev_set_unique); >> >> +/** >> + * drm_drv_enabled - Checks if a DRM driver can be enabled >> + * @driver: DRM driver to check >> + * >> + * Checks whether a DRM driver can be enabled or not. This may be the case >> + * if the "nomodeset" kernel command line parameter is used. >> + * >> + * Return: 0 on success or a negative error code on failure. >> + */ >> +int drm_drv_enabled(const struct drm_driver *driver) >> +{ >> + if (vgacon_text_force()) { >> + DRM_INFO("%s driver is disabled\n", driver->name); > > DRM_INFO is deprecated, please do not use it in new code. > Also other users had an error message and not just info - is info > enough? > > >> + return -ENODEV; >> + } >> + >> + return 0; >> +} >> +EXPORT_SYMBOL(drm_drv_enabled); >> + >> /* >> * DRM Core >> * The DRM core module initializes all global DRM objects and makes them >> diff --git a/drivers/gpu/drm/i915/i915_module.c b/drivers/gpu/drm/i915/i915_module.c >> index ab2295dd4500..45cb3e540eff 100644 >> --- a/drivers/gpu/drm/i915/i915_module.c >> +++ b/drivers/gpu/drm/i915/i915_module.c >> @@ -18,9 +18,12 @@ >> #include "i915_selftest.h" >> #include "i915_vma.h" >> >> +static const struct drm_driver driver; > Hmmm... > >> + >> static int i915_check_nomodeset(void) >> { >> bool use_kms = true; >> + int ret; >> >> /* >> * Enable KMS by default, unless explicitly overriden by >> @@ -31,7 +34,8 @@ static int i915_check_nomodeset(void) >> if (i915_modparams.modeset == 0) >> use_kms = false; >> >> - if (vgacon_text_force() && i915_modparams.modeset == -1) >> + ret = drm_drv_enabled(&driver); > > You pass the local driver variable here - which looks wrong as this is > not the same as the driver variable declared in another file. Indeed. > Maybe move the check to new function you can add to init_funcs, > and locate the new function in i915_drv - so it has access to driver? We don't really want that, though. This check is pretty much as early as it can be, and there's a ton of useless initialization that would happen if we waited until drm_driver is available. >From my POV, drm_drv_enabled() is a solution that creates a worse problem for us than it solves. BR, Jani. > > > Sam -- Jani Nikula, Intel Open Source Graphics Center