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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9D0D6C04A6A for ; Fri, 21 Jul 2023 16:33:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229704AbjGUQda (ORCPT ); Fri, 21 Jul 2023 12:33:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33162 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230449AbjGUQcv (ORCPT ); Fri, 21 Jul 2023 12:32:51 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 77A8F3AAF for ; Fri, 21 Jul 2023 09:31:26 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2A4A361D29 for ; Fri, 21 Jul 2023 16:22:16 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A50BC433C8; Fri, 21 Jul 2023 16:22:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1689956535; bh=xcIVbpObT/svD7GPW3bBgc0B9suwTdnX4OSop4Vmv08=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=11xcGOG/L6JY1Ei6XJXlNRPXOIZp53DtrojK6Pb+Tm8JxUti0yvXKSnoeOBKll5vQ BPFOSAyavoH5ZibLk4tPqrK0vW/APgyTRmU3rVPMG0bynR0VX3cJ99xqz3Hsw3eZoN YEhuiyQZCjZ8SSEQ/MmsEa2KDAZdHCW9crTEnlOU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Brian Norris , Sean Paul Subject: [PATCH 6.4 194/292] drm/atomic: Allow vblank-enabled + self-refresh "disable" Date: Fri, 21 Jul 2023 18:05:03 +0200 Message-ID: <20230721160537.223050555@linuxfoundation.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230721160528.800311148@linuxfoundation.org> References: <20230721160528.800311148@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Brian Norris commit 9d0e3cac3517942a6e00eeecfe583a98715edb16 upstream. The self-refresh helper framework overloads "disable" to sometimes mean "go into self-refresh mode," and this mode activates automatically (e.g., after some period of unchanging display output). In such cases, the display pipe is still considered "on", and user-space is not aware that we went into self-refresh mode. Thus, users may expect that vblank-related features (such as DRM_IOCTL_WAIT_VBLANK) still work properly. However, we trigger the WARN_ONCE() here if a CRTC driver tries to leave vblank enabled. Add a different expectation: that CRTCs *should* leave vblank enabled when going into self-refresh. This patch is preparation for another patch -- "drm/rockchip: vop: Leave vblank enabled in self-refresh" -- which resolves conflicts between the above self-refresh behavior and the API tests in IGT's kms_vblank test module. == Some alternatives discussed: == It's likely that on many display controllers, vblank interrupts will turn off when the CRTC is disabled, and so in some cases, self-refresh may not support vblank. To support such cases, we might consider additions to the generic helpers such that we fire vblank events based on a timer. However, there is currently only one driver using the common self-refresh helpers (i.e., rockchip), and at least as of commit bed030a49f3e ("drm/rockchip: Don't fully disable vop on self refresh"), the CRTC hardware is powered enough to continue to generate vblank interrupts. So we chose the simpler option of leaving vblank interrupts enabled. We can reevaluate this decision and perhaps augment the helpers if/when we gain a second driver that has different requirements. v3: * include discussion summary v2: * add 'ret != 0' warning case for self-refresh * describe failing test case and relation to drm/rockchip patch better Cc: # dependency for "drm/rockchip: vop: Leave # vblank enabled in self-refresh" Signed-off-by: Brian Norris Signed-off-by: Sean Paul Link: https://patchwork.freedesktop.org/patch/msgid/20230109171809.v3.1.I3904f697863649eb1be540ecca147a66e42bfad7@changeid Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_atomic_helper.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -1209,7 +1209,16 @@ disable_outputs(struct drm_device *dev, continue; ret = drm_crtc_vblank_get(crtc); - WARN_ONCE(ret != -EINVAL, "driver forgot to call drm_crtc_vblank_off()\n"); + /* + * Self-refresh is not a true "disable"; ensure vblank remains + * enabled. + */ + if (new_crtc_state->self_refresh_active) + WARN_ONCE(ret != 0, + "driver disabled vblank in self-refresh\n"); + else + WARN_ONCE(ret != -EINVAL, + "driver forgot to call drm_crtc_vblank_off()\n"); if (ret == 0) drm_crtc_vblank_put(crtc); }