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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 7296BCEB2FE for ; Tue, 1 Oct 2024 05:08:27 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id DFEDE10E5D3; Tue, 1 Oct 2024 05:08:26 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="Tyw1cA8W"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.8]) by gabe.freedesktop.org (Postfix) with ESMTPS id 026EE10E5D2; Tue, 1 Oct 2024 05:08:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1727759306; x=1759295306; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=Jc926JMUqMfDTY9f3p0BkuZbbOcDWoJTXcsE626tssI=; b=Tyw1cA8WSSOYqb2zkS0yhzceLOOipJ51KcYkwaJT/G4YjNwFw/Vim19/ M7FExCV1kR9cNtVJCDFDIGLTVUnTeq4sSl1WLYhakfuIT7iFedT4XflD5 8xQMSqn+c9OecL3ucaLFjaaPwU+wElu5eolvpCGwbejDVKxyctIm1gJpg G4ktBdnNQAtdN2FSLwvtP8ERYlRnhr3HCBZzPXRscdp0DAJIFzuxmMEtv JfoaJWEl7+ZAV0nVPNtMIaun6KcROtF5bpk1pthpJkUJFP9PpFlI1bm8j dzzUcFrJf0cJV8Ytro6SLZl67fr1DQBHjzZ2so8xXNvgeigHHfxpPlFtR w==; X-CSE-ConnectionGUID: 03gfmaUzQna88Rm4+MwncA== X-CSE-MsgGUID: BvdNPO4qTEa6grWhNLVWCQ== X-IronPort-AV: E=McAfee;i="6700,10204,11211"; a="44394592" X-IronPort-AV: E=Sophos;i="6.11,167,1725346800"; d="scan'208";a="44394592" Received: from orviesa003.jf.intel.com ([10.64.159.143]) by fmvoesa102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2024 22:08:25 -0700 X-CSE-ConnectionGUID: oQXximSvS7CNbuDY6uyZjg== X-CSE-MsgGUID: 8QxW98/OTHGCAMvj2NFBwA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,167,1725346800"; d="scan'208";a="78382591" Received: from black.fi.intel.com ([10.237.72.28]) by orviesa003.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 30 Sep 2024 22:08:22 -0700 Date: Tue, 1 Oct 2024 08:08:18 +0300 From: Raag Jadav To: Andy Shevchenko Cc: airlied@gmail.com, simona@ffwll.ch, lucas.demarchi@intel.com, thomas.hellstrom@linux.intel.com, rodrigo.vivi@intel.com, jani.nikula@linux.intel.com, joonas.lahtinen@linux.intel.com, tursulin@ursulin.net, lina@asahilina.net, intel-xe@lists.freedesktop.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, himal.prasad.ghimiray@intel.com, francois.dugast@intel.com, aravind.iddamsetty@linux.intel.com, anshuman.gupta@intel.com, andi.shyti@linux.intel.com, matthew.d.roper@intel.com Subject: Re: [PATCH v7 1/5] drm: Introduce device wedged event Message-ID: References: <20240930073845.347326-1-raag.jadav@intel.com> <20240930073845.347326-2-raag.jadav@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Mon, Sep 30, 2024 at 03:59:59PM +0300, Andy Shevchenko wrote: > On Mon, Sep 30, 2024 at 01:08:41PM +0530, Raag Jadav wrote: > > Introduce device wedged event, which will notify userspace of wedged > > (hanged/unusable) state of the DRM device through a uevent. This is > > useful especially in cases where the device is no longer operating as > > expected even after a hardware reset and has become unrecoverable from > > driver context. > > > > Purpose of this implementation is to provide drivers a generic way to > > recover with the help of userspace intervention. Different drivers may > > have different ideas of a "wedged device" depending on their hardware > > implementation, and hence the vendor agnostic nature of the event. > > It is up to the drivers to decide when they see the need for recovery > > and how they want to recover from the available methods. > > > > Current implementation defines three recovery methods, out of which, > > drivers can choose to support any one or multiple of them. Preferred > > recovery method will be sent in the uevent environment as WEDGED=. > > Userspace consumers (sysadmin) can define udev rules to parse this event > > and take respective action to recover the device. > > > > =============== ================================== > > Recovery method Consumer expectations > > =============== ================================== > > rebind unbind + rebind driver > > bus-reset unbind + reset bus device + rebind > > reboot reboot system > > =============== ================================== > > ... > > > +/* > > + * Available recovery methods for wedged device. To be sent along with device > > + * wedged uevent. > > + */ > > +static const char *const drm_wedge_recovery_opts[] = { > > + [DRM_WEDGE_RECOVERY_REBIND] = "rebind", > > + [DRM_WEDGE_RECOVERY_BUS_RESET] = "bus-reset", > > + [DRM_WEDGE_RECOVERY_REBOOT] = "reboot", > > +}; > > Place for static_assert() is here, as it closer to the actual data we test... Shouldn't it be at the point of access? If no, why do we care about the data when it's not being used? > > +static bool drm_wedge_recovery_is_valid(enum drm_wedge_recovery method) > > +{ > > + static_assert(ARRAY_SIZE(drm_wedge_recovery_opts) == DRM_WEDGE_RECOVERY_MAX); > > ...it doesn't fully belong to this function (or only to this function). The purpose of having a helper is to have a single point of access, no? Side note: It also goes well with is_valid() semantic IMHO. > > + return method >= DRM_WEDGE_RECOVERY_REBIND && method < DRM_WEDGE_RECOVERY_MAX; > > +} > > Why do we need this one-liner (after above comment being addressed) as a > separate function? I'm not sure if I'm following you. Method is not a constant here, we'll get it on the stack. Raag