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=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,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 07A4DC282DD for ; Thu, 23 May 2019 20:38:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4FB8217D9 for ; Thu, 23 May 2019 20:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387973AbfEWUiF (ORCPT ); Thu, 23 May 2019 16:38:05 -0400 Received: from relay12.mail.gandi.net ([217.70.178.232]:49727 "EHLO relay12.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387394AbfEWUiF (ORCPT ); Thu, 23 May 2019 16:38:05 -0400 Received: from localhost (lfbn-1-10718-76.w90-89.abo.wanadoo.fr [90.89.68.76]) (Authenticated sender: maxime.ripard@bootlin.com) by relay12.mail.gandi.net (Postfix) with ESMTPSA id 860A2200006; Thu, 23 May 2019 20:37:55 +0000 (UTC) Date: Thu, 23 May 2019 22:37:54 +0200 From: Maxime Ripard To: Jagan Teki Cc: David Airlie , Daniel Vetter , Chen-Yu Tsai , dri-devel@lists.freedesktop.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, bshah@mykolab.com, Vasily Khoruzhick , powerpan@qq.com, michael@amarulasolutions.com, linux-amarula@amarulasolutions.com, linux-sunxi@googlegroups.com Subject: Re: [PATCH v10 02/11] drm/sun4i: dsi: Update start value in video start delay Message-ID: <20190523203754.2lhi37veeh4rwiy3@flea> References: <20190520090318.27570-1-jagan@amarulasolutions.com> <20190520090318.27570-3-jagan@amarulasolutions.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190520090318.27570-3-jagan@amarulasolutions.com> User-Agent: NeoMutt/20180716 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 20, 2019 at 02:33:09PM +0530, Jagan Teki wrote: > start value in video start delay computation done in below commit > is as per the legacy bsp drivers/video/sunxi/legacy.. > "drm/sun4i: dsi: Change the start delay calculation" > (sha1: da676c6aa6413d59ab0a80c97bbc273025e640b2) > > This existing start delay computation gives start value of 35, > for "bananapi,s070wv20-ct16" panel timings which indeed trigger > panel flip_done timed out as: > > WARNING: CPU: 0 PID: 31 at drivers/gpu/drm/drm_atomic_helper.c:1429 drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0 > [CRTC:46:crtc-0] vblank wait timed out > Modules linked in: > CPU: 0 PID: 31 Comm: kworker/0:1 Tainted: G W 5.1.0-next-20190514-00025-gf928bc7cc146 #15 > Hardware name: Allwinner sun8i Family > Workqueue: events deferred_probe_work_func > [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > [] (show_stack) from [] (dump_stack+0x84/0x98) > [] (dump_stack) from [] (__warn+0xfc/0x114) > [] (__warn) from [] (warn_slowpath_fmt+0x44/0x68) > [] (warn_slowpath_fmt) from [] (drm_atomic_helper_wait_for_vblanks.part.1+0x298/0x2a0) > [] (drm_atomic_helper_wait_for_vblanks.part.1) from [] (drm_atomic_helper_commit_tail_rpm+0x5c/0x6c) > [] (drm_atomic_helper_commit_tail_rpm) from [] (commit_tail+0x40/0x6c) > [] (commit_tail) from [] (drm_atomic_helper_commit+0xbc/0x128) > [] (drm_atomic_helper_commit) from [] (restore_fbdev_mode_atomic+0x1cc/0x1dc) > [] (restore_fbdev_mode_atomic) from [] (drm_fb_helper_pan_display+0xac/0x1d0) > [] (drm_fb_helper_pan_display) from [] (fb_pan_display+0xcc/0x134) > [] (fb_pan_display) from [] (bit_update_start+0x14/0x30) > [] (bit_update_start) from [] (fbcon_switch+0x3d8/0x4e0) > [] (fbcon_switch) from [] (redraw_screen+0x174/0x238) > [] (redraw_screen) from [] (fbcon_prepare_logo+0x3c4/0x400) > [] (fbcon_prepare_logo) from [] (fbcon_init+0x3c8/0x5ac) > [] (fbcon_init) from [] (visual_init+0xbc/0x104) > [] (visual_init) from [] (do_bind_con_driver+0x1b0/0x390) > [] (do_bind_con_driver) from [] (do_take_over_console+0x13c/0x1c4) > [] (do_take_over_console) from [] (do_fbcon_takeover+0x74/0xcc) > [] (do_fbcon_takeover) from [] (notifier_call_chain+0x44/0x84) > [] (notifier_call_chain) from [] (__blocking_notifier_call_chain+0x48/0x60) > [] (__blocking_notifier_call_chain) from [] (blocking_notifier_call_chain+0x18/0x20) > [] (blocking_notifier_call_chain) from [] (register_framebuffer+0x1e0/0x2f8) > [] (register_framebuffer) from [] (__drm_fb_helper_initial_config_and_unlock+0x2fc/0x50c) > [] (__drm_fb_helper_initial_config_and_unlock) from [] (drm_fbdev_client_hotplug+0xe8/0x1b8) > [] (drm_fbdev_client_hotplug) from [] (drm_fbdev_generic_setup+0x88/0x118) > [] (drm_fbdev_generic_setup) from [] (sun4i_drv_bind+0x128/0x160) > [] (sun4i_drv_bind) from [] (try_to_bring_up_master+0x164/0x1a0) > [] (try_to_bring_up_master) from [] (__component_add+0x94/0x140) > [] (__component_add) from [] (sun6i_dsi_probe+0x144/0x234) > [] (sun6i_dsi_probe) from [] (platform_drv_probe+0x48/0x9c) > [] (platform_drv_probe) from [] (really_probe+0x1dc/0x2c8) > [] (really_probe) from [] (driver_probe_device+0x60/0x160) > [] (driver_probe_device) from [] (bus_for_each_drv+0x74/0xb8) > [] (bus_for_each_drv) from [] (__device_attach+0xd0/0x13c) > [] (__device_attach) from [] (bus_probe_device+0x84/0x8c) > [] (bus_probe_device) from [] (deferred_probe_work_func+0x64/0x90) > [] (deferred_probe_work_func) from [] (process_one_work+0x204/0x420) > [] (process_one_work) from [] (worker_thread+0x274/0x5a0) > [] (worker_thread) from [] (kthread+0x11c/0x14c) > [] (kthread) from [] (ret_from_fork+0x14/0x2c) > Exception stack(0xde539fb0 to 0xde539ff8) > 9fa0: 00000000 00000000 00000000 00000000 > 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000 > 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000 > ---[ end trace 755e10f62b83f396 ]--- > Console: switching to colour frame buffer device 100x30 > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CRTC:46:crtc-0] flip_done timed out > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [CONNECTOR:48:DSI-1] flip_done timed out > [drm:drm_atomic_helper_wait_for_dependencies] *ERROR* [PLANE:30:plane-0] flip_done timed out > > But the expected start delay value is 1 which is confirmed from > new bsp [2]. If you're saying that the "legacy" link (second one) is the new BSP. > The important and unclear note on legacy and new bsp codes [1] [2] > is both use similar start computation initially but it later reassign > it to 1 in new bsp. Then start_delay is never reassigned to 1 in that link, and is clamped between 8 and 100 as the code that you are removing is doing. > Unfortunately we don't have any evidence or documentation for this > reassignment to 1 in new bsp, but it is working with all supported > panels in A33, A64. No, it's not. That was added to fix a panel that is supported today. Maxime -- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com