From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.kernel.org ([198.145.29.99]:37124 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732084AbeK3BfT (ORCPT ); Thu, 29 Nov 2018 20:35:19 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Paul Kocialkowski , Boris Brezillon , Maxime Ripard , Daniel Vetter Subject: [PATCH 4.19 040/110] drm/fb-helper: Blacklist writeback when adding connectors to fbdev Date: Thu, 29 Nov 2018 15:12:11 +0100 Message-Id: <20181129135922.880925714@linuxfoundation.org> In-Reply-To: <20181129135921.231283053@linuxfoundation.org> References: <20181129135921.231283053@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: 4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Paul Kocialkowski commit 8fd3b90300bec541806dac271de2fd44e2e4e2d2 upstream. Writeback connectors do not produce any on-screen output and require special care for use. Such connectors are hidden from enumeration in DRM resources by default, but they are still picked-up by fbdev. This makes rather little sense since fbdev is not really adapted for dealing with writeback. Moreover, this is also a source of issues when userspace disables the CRTC (and associated plane) without detaching the CRTC from the connector (which is hidden by default). In this case, the connector is still using the CRTC, leading to am "enabled/connectors mismatch" and eventually the failure of the associated atomic commit. This situation happens with VC4 testing under IGT GPU Tools. Filter out writeback connectors in the fbdev helper to solve this. Signed-off-by: Paul Kocialkowski Reviewed-by: Boris Brezillon Reviewed-by: Maxime Ripard Tested-by: Maxime Ripard Fixes: 935774cd71fe ("drm: Add writeback connector type") Cc: # v4.19+ Signed-off-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20181115163248.21168-1-paul.kocialkowski@bootlin.com Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_fb_helper.c | 3 +++ 1 file changed, 3 insertions(+) --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -200,6 +200,9 @@ int drm_fb_helper_single_add_all_connect mutex_lock(&fb_helper->lock); drm_connector_list_iter_begin(dev, &conn_iter); drm_for_each_connector_iter(connector, &conn_iter) { + if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK) + continue; + ret = __drm_fb_helper_add_one_connector(fb_helper, connector); if (ret) goto fail;