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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_NEOMUTT 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 5624CC65C20 for ; Mon, 8 Oct 2018 14:52:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1B99D20858 for ; Mon, 8 Oct 2018 14:52:27 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="Ky91l1EB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B99D20858 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726491AbeJHWEb (ORCPT ); Mon, 8 Oct 2018 18:04:31 -0400 Received: from mail-qk1-f193.google.com ([209.85.222.193]:45243 "EHLO mail-qk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726198AbeJHWEb (ORCPT ); Mon, 8 Oct 2018 18:04:31 -0400 Received: by mail-qk1-f193.google.com with SMTP id m8-v6so12202184qka.12; Mon, 08 Oct 2018 07:52:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition :content-transfer-encoding:user-agent; bh=i3VL7enVUB8mmUR8iuBXBuDcOmQd/t6YsKyhYNxMpxE=; b=Ky91l1EBiQzjvRdVgNTn8s2iUhlQqN4dYHJmP+rWZvVaN3GsPiqZA1NlS8hdSY2Fiu 9U7dnbkQsjtbWVmMixchrz0PoHvbM8sQjRXpXBFmbbaQBJCRsebcrT+me4T8lbVs0RNS MbwvV/TGR3yWa3cUjl5Lhz3tSrL/I4KwS+X2VHP0eiP3H4fI4894eiI12KJtSE/mOam5 wLGB3xWZsjLbrmF/VkrMlbqTw3nssjCyCnQNCBAXnxVVkThkNi8fXtPntryBrkbemHbx OTsojCmNlA3jNB6xuW8wgx6E4pbRchFa1dgLMMguGI85kYbNe2Hlc1H170CHIp0d9No/ tUmw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition:content-transfer-encoding:user-agent; bh=i3VL7enVUB8mmUR8iuBXBuDcOmQd/t6YsKyhYNxMpxE=; b=nfWTTbwVf+ZjirD9hwL7gTlYhVQmxs9VOPKBz7YBdamOGUmBpbKJofHL1ZOP6EkhtL 5FjaH3BvrA6x/oOFTuTVLbtfUCBxST3+olXTOCMT6Qqmn7+93Z7Rs5aOMMWp+OVXI1bR kXvIWBdohLAm6jiTq91arjwG2+703HyWi0DoW3+QwCvYWdHZJ/b3rj5GeJ3lkvrVCg6i KZ4+iCXvGMxScqwIQsMJutMmEVZs4dKwVnlT+E3VziZ1yWR9BQO+usqb10XRrK8bVM21 N9DKG0fzqP4oCtc1TpLcaRZvGDxaLqxxjkYWZugLMNap1ulp5rwW9jFjUfs0yt4j3SlE yw0w== X-Gm-Message-State: ABuFfoih7CvD2nb6NtzMhWDtVpJW3cXdhwd61XNZVx1qxJJazmhhucCb 84SaL5e+F53EUrwMv5SVQb8= X-Google-Smtp-Source: ACcGV62OQyzwTqg067hnjclUlglCwh6o0qarFHJ7KD32zB1yRH6kBNAOWAGJrqnYxjer0dj42qQOzg== X-Received: by 2002:ae9:e507:: with SMTP id w7-v6mr18760728qkf.246.1539010344305; Mon, 08 Oct 2018 07:52:24 -0700 (PDT) Received: from smtp.gmail.com ([143.107.45.1]) by smtp.gmail.com with ESMTPSA id m54-v6sm4045414qtb.97.2018.10.08.07.52.21 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Mon, 08 Oct 2018 07:52:23 -0700 (PDT) Date: Mon, 8 Oct 2018 11:52:20 -0300 From: Rodrigo Siqueira To: Gustavo Padovan , Maarten Lankhorst , Sean Paul , David Airlie , Daniel Vetter Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, kernel-janitors@vger.kernel.org Subject: [PATCH] drm/drm_vblank: Change EINVAL by the correct errno Message-ID: <20181008145220.p34dllgsiw6rlpod@smtp.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 ENOTTY (Inappropriate ioctl for device). Additionally, some operations are unsupported by this function, and returns EINVAL; this patch changes the return value to EOPNOTSUPP (Operation not supported). 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. Signed-off-by: Rodrigo Siqueira --- drivers/gpu/drm/drm_vblank.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/drm_vblank.c b/drivers/gpu/drm/drm_vblank.c index 98e091175921..88ec6fb49afb 100644 --- a/drivers/gpu/drm/drm_vblank.c +++ b/drivers/gpu/drm/drm_vblank.c @@ -1533,10 +1533,10 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, unsigned int flags, pipe, high_pipe; if (!dev->irq_enabled) - return -EINVAL; + return -ENOTTY; if (vblwait->request.type & _DRM_VBLANK_SIGNAL) - return -EINVAL; + return -EOPNOTSUPP; if (vblwait->request.type & ~(_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | @@ -1545,7 +1545,7 @@ int drm_wait_vblank_ioctl(struct drm_device *dev, void *data, vblwait->request.type, (_DRM_VBLANK_TYPES_MASK | _DRM_VBLANK_FLAGS_MASK | _DRM_VBLANK_HIGH_CRTC_MASK)); - return -EINVAL; + return -EOPNOTSUPP; } flags = vblwait->request.type & _DRM_VBLANK_FLAGS_MASK; -- 2.19.0