From patchwork Wed Apr 28 09:25:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Lindgren X-Patchwork-Id: 12228405 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 22835C433B4 for ; Wed, 28 Apr 2021 09:25:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DAF2061424 for ; Wed, 28 Apr 2021 09:25:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230113AbhD1JZz (ORCPT ); Wed, 28 Apr 2021 05:25:55 -0400 Received: from muru.com ([72.249.23.125]:49464 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230041AbhD1JZy (ORCPT ); Wed, 28 Apr 2021 05:25:54 -0400 Received: from hillo.muru.com (localhost [127.0.0.1]) by muru.com (Postfix) with ESMTP id B608B80AA; Wed, 28 Apr 2021 09:25:09 +0000 (UTC) From: Tony Lindgren To: Tomi Valkeinen Cc: Laurent Pinchart , Sebastian Reichel , dri-devel@lists.freedesktop.org, linux-omap@vger.kernel.org Subject: [PATCHv2] drm/omap: Fix issue with clocks left on after resume Date: Wed, 28 Apr 2021 12:25:00 +0300 Message-Id: <20210428092500.23521-1-tony@atomide.com> X-Mailer: git-send-email 2.31.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org On resume, dispc pm_runtime_force_resume() is not enabling the hardware as we pass the pm_runtime_need_not_resume() test as the device is suspended with no child devices. As the resume continues, omap_atomic_comit_tail() calls dispc_runtime_get() that calls rpm_resume() enabling the hardware, and increasing child_count for it's parent device. But at this point device_complete() has not yet been called for dispc. So when omap_atomic_comit_tail() calls dispc_runtime_put(), it won't idle the hardware as rpm_suspend() returns -EBUSY, and the clocks are left on after resume. The parent child count is not decremented as the -EBUSY cannot be easily handled until later on after device_complete(). This can be easily seen for example after suspending Beagleboard-X15 with no displays connected, and by reading the CM_DSS_DSS_CLKCTRL register at 0x4a009120 after resume. After a suspend and resume cycle, it shows a value of 0x00040102 instead of 0x00070000 like it should. Let's fix the issue by calling dispc_runtime_suspend() and dispc_runtime_resume() directly from dispc_suspend() and dispc_resume(). This leaves out the PM runtime related issues for system suspend. We could handle the issue by adding more calls to dispc_runtime_get() and dispc_runtime_put() from omap_drm_suspend() and omap_drm_resume() as suggested by Tomi Valkeinen . But that would just add more inter-component calls and more dependencies to PM runtime for system suspend and does not make things easier in the long. See also earlier commit 88d26136a256 ("PM: Prevent runtime suspend during system resume") and commit ca8199f13498 ("drm/msm/dpu: ensure device suspend happens during PM sleep") for more information. Fixes: ecfdedd7da5d ("drm/omap: force runtime PM suspend on system suspend") Signed-off-by: Tony Lindgren --- Changes since v1: - Updated the description for a typo noticed by Tomi - Added more info about what all goes wrong --- drivers/gpu/drm/omapdrm/dss/dispc.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/omapdrm/dss/dispc.c b/drivers/gpu/drm/omapdrm/dss/dispc.c --- a/drivers/gpu/drm/omapdrm/dss/dispc.c +++ b/drivers/gpu/drm/omapdrm/dss/dispc.c @@ -182,6 +182,7 @@ struct dispc_device { const struct dispc_features *feat; bool is_enabled; + bool needs_resume; struct regmap *syscon_pol; u32 syscon_pol_offset; @@ -4887,10 +4888,34 @@ static int dispc_runtime_resume(struct device *dev) return 0; } +static int dispc_suspend(struct device *dev) +{ + struct dispc_device *dispc = dev_get_drvdata(dev); + + if (!dispc->is_enabled) + return 0; + + dispc->needs_resume = true; + + return dispc_runtime_suspend(dev); +} + +static int dispc_resume(struct device *dev) +{ + struct dispc_device *dispc = dev_get_drvdata(dev); + + if (!dispc->needs_resume) + return 0; + + dispc->needs_resume = false; + + return dispc_runtime_resume(dev); +} + static const struct dev_pm_ops dispc_pm_ops = { .runtime_suspend = dispc_runtime_suspend, .runtime_resume = dispc_runtime_resume, - SET_LATE_SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume) + SET_LATE_SYSTEM_SLEEP_PM_OPS(dispc_suspend, dispc_resume) }; struct platform_driver omap_dispchw_driver = {