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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 33F3CC31E4B for ; Fri, 14 Jun 2019 17:20:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 155AC2183E for ; Fri, 14 Jun 2019 17:20:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726358AbfFNRU2 (ORCPT ); Fri, 14 Jun 2019 13:20:28 -0400 Received: from mga07.intel.com ([134.134.136.100]:55329 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725837AbfFNRU1 (ORCPT ); Fri, 14 Jun 2019 13:20:27 -0400 X-Amp-Result: UNSCANNABLE X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 14 Jun 2019 10:20:27 -0700 X-ExtLoop1: 1 Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.174]) by orsmga006.jf.intel.com with SMTP; 14 Jun 2019 10:20:23 -0700 Received: by stinkbox (sSMTP sendmail emulation); Fri, 14 Jun 2019 20:20:22 +0300 Date: Fri, 14 Jun 2019 20:20:22 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Sam Ravnborg Cc: Rodrigo Siqueira , Maxime Ripard , kernel-janitors@vger.kernel.org, intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, David Airlie , Sean Paul Subject: Re: Drop use of DRM_WAIT_ON() [Was: drm/drm_vblank: Change EINVAL by the correct errno] Message-ID: <20190614172022.GE5942@intel.com> References: <20190613021054.cdewdb3azy6zuoyw@smtp.gmail.com> <20190613050403.GA21502@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20190613050403.GA21502@ravnborg.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 13, 2019 at 07:04:03AM +0200, Sam Ravnborg wrote: > Hi Rodrigo. > > On Wed, Jun 12, 2019 at 11:10:54PM -0300, Rodrigo Siqueira wrote: > > For historical reason, the function drm_wait_vblank_ioctl always return > > -EINVAL if something gets wrong. This scenario limits the flexibility > > for the userspace make detailed verification of the problem and take > > some action. In particular, the validation of “if (!dev->irq_enabled)” > > in the drm_wait_vblank_ioctl is responsible for checking if the driver > > support vblank or not. If the driver does not support VBlank, the > > function drm_wait_vblank_ioctl returns EINVAL which does not represent > > the real issue; this patch changes this behavior by return EOPNOTSUPP. > > Additionally, some operations are unsupported by this function, and > > returns EINVAL; this patch also changes the return value to EOPNOTSUPP > > in this case. Lastly, the function drm_wait_vblank_ioctl is invoked by > > libdrm, which is used by many compositors; because of this, it is > > important to check if this change breaks any compositor. In this sense, > > the following projects were examined: > > > > * Drm-hwcomposer > > * Kwin > > * Sway > > * Wlroots > > * Wayland-core > > * Weston > > * Xorg (67 different drivers) > > > > For each repository the verification happened in three steps: > > > > * Update the main branch > > * Look for any occurrence "drmWaitVBlank" with the command: > > git grep -n "drmWaitVBlank" > > * Look in the git history of the project with the command: > > git log -SdrmWaitVBlank > > > > Finally, none of the above projects validate the use of EINVAL which > > make safe, at least for these projects, to change the return values. > > > > Change since V2: > > Daniel Vetter and Chris Wilson > > - Replace ENOTTY by EOPNOTSUPP > > - Return EINVAL if the parameters are wrong > > > > Signed-off-by: Rodrigo Siqueira > > --- > > Update: > > Now IGT has a way to validate if a driver has vblank support or not. > > See: https://gitlab.freedesktop.org/drm/igt-gpu-tools/commit/2d244aed69165753f3adbbd6468db073dc1acf9A > > > > drivers/gpu/drm/drm_vblank.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > > index 0d704bddb1a6..d76a783a7d4b 100644 > > --- a/drivers/gpu/drm/drm_vblank.c > > +++ b/drivers/gpu/drm/drm_vblank.c > > @@ -1578,10 +1578,10 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, > > unsigned int flags, pipe, high_pipe; > > > > if (!dev->irq_enabled) > > - return -EINVAL; > > + return -EOPNOTSUPP; > > > > if (vblwait->request.type & _DRM_VBLANK_SIGNAL) > > - return -EINVAL; > > + return -EOPNOTSUPP; > > > > if (vblwait->request.type & > > ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | > > When touching this function, could I ask you to take a look at > eliminating the use of DRM_WAIT_ON()? > It comes from the deprecated drm_os_linux.h header, and it is only of > the few remaining users of DRM_WAIT_ON(). IIRC all previous attempts at removing that ended up with regressions. I think there are some dragons lurking inside that macro. -- Ville Syrjälä Intel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Date: Fri, 14 Jun 2019 17:20:22 +0000 Subject: Re: Drop use of DRM_WAIT_ON() [Was: drm/drm_vblank: Change EINVAL by the correct errno] Message-Id: <20190614172022.GE5942@intel.com> List-Id: References: <20190613021054.cdewdb3azy6zuoyw@smtp.gmail.com> <20190613050403.GA21502@ravnborg.org> In-Reply-To: <20190613050403.GA21502@ravnborg.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Sam Ravnborg Cc: Rodrigo Siqueira , Maxime Ripard , intel-gfx@lists.freedesktop.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, David Airlie , Sean Paul On Thu, Jun 13, 2019 at 07:04:03AM +0200, Sam Ravnborg wrote: > Hi Rodrigo. > > On Wed, Jun 12, 2019 at 11:10:54PM -0300, Rodrigo Siqueira wrote: > > For historical reason, the function drm_wait_vblank_ioctl always return > > -EINVAL if something gets wrong. This scenario limits the flexibility > > for the userspace make detailed verification of the problem and take > > some action. In particular, the validation of “if (!dev->irq_enabled)” > > in the drm_wait_vblank_ioctl is responsible for checking if the driver > > support vblank or not. If the driver does not support VBlank, the > > function drm_wait_vblank_ioctl returns EINVAL which does not represent > > the real issue; this patch changes this behavior by return EOPNOTSUPP. > > Additionally, some operations are unsupported by this function, and > > returns EINVAL; this patch also changes the return value to EOPNOTSUPP > > in this case. Lastly, the function drm_wait_vblank_ioctl is invoked by > > libdrm, which is used by many compositors; because of this, it is > > important to check if this change breaks any compositor. In this sense, > > the following projects were examined: > > > > * Drm-hwcomposer > > * Kwin > > * Sway > > * Wlroots > > * Wayland-core > > * Weston > > * Xorg (67 different drivers) > > > > For each repository the verification happened in three steps: > > > > * Update the main branch > > * Look for any occurrence "drmWaitVBlank" with the command: > > git grep -n "drmWaitVBlank" > > * Look in the git history of the project with the command: > > git log -SdrmWaitVBlank > > > > Finally, none of the above projects validate the use of EINVAL which > > make safe, at least for these projects, to change the return values. > > > > Change since V2: > > Daniel Vetter and Chris Wilson > > - Replace ENOTTY by EOPNOTSUPP > > - Return EINVAL if the parameters are wrong > > > > Signed-off-by: Rodrigo Siqueira > > --- > > Update: > > Now IGT has a way to validate if a driver has vblank support or not. > > See: https://gitlab.freedesktop.org/drm/igt-gpu-tools/commit/2d244aed69165753f3adbbd6468db073dc1acf9A > > > > drivers/gpu/drm/drm_vblank.c | 4 ++-- > > 1 file changed, 2 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c > > index 0d704bddb1a6..d76a783a7d4b 100644 > > --- a/drivers/gpu/drm/drm_vblank.c > > +++ b/drivers/gpu/drm/drm_vblank.c > > @@ -1578,10 +1578,10 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, > > unsigned int flags, pipe, high_pipe; > > > > if (!dev->irq_enabled) > > - return -EINVAL; > > + return -EOPNOTSUPP; > > > > if (vblwait->request.type & _DRM_VBLANK_SIGNAL) > > - return -EINVAL; > > + return -EOPNOTSUPP; > > > > if (vblwait->request.type & > > ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | > > When touching this function, could I ask you to take a look at > eliminating the use of DRM_WAIT_ON()? > It comes from the deprecated drm_os_linux.h header, and it is only of > the few remaining users of DRM_WAIT_ON(). IIRC all previous attempts at removing that ended up with regressions. I think there are some dragons lurking inside that macro. -- Ville Syrjälä Intel From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= Subject: Re: Drop use of DRM_WAIT_ON() [Was: drm/drm_vblank: Change EINVAL by the correct errno] Date: Fri, 14 Jun 2019 20:20:22 +0300 Message-ID: <20190614172022.GE5942@intel.com> References: <20190613021054.cdewdb3azy6zuoyw@smtp.gmail.com> <20190613050403.GA21502@ravnborg.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <20190613050403.GA21502@ravnborg.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Sam Ravnborg Cc: Rodrigo Siqueira , Maxime Ripard , intel-gfx@lists.freedesktop.org, kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, David Airlie , Sean Paul List-Id: 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