From patchwork Tue Oct 20 15:46:56 2015 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Russell King - ARM Linux X-Patchwork-Id: 7448491 Return-Path: X-Original-To: patchwork-dmaengine@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id 2F1E7BEEA4 for ; Tue, 20 Oct 2015 15:47:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id B949720842 for ; Tue, 20 Oct 2015 15:47:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9F0722084E for ; Tue, 20 Oct 2015 15:47:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751578AbbJTPrs (ORCPT ); Tue, 20 Oct 2015 11:47:48 -0400 Received: from pandora.arm.linux.org.uk ([78.32.30.218]:50927 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750846AbbJTPro (ORCPT ); Tue, 20 Oct 2015 11:47:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=arm.linux.org.uk; s=pandora-2014; h=Sender:In-Reply-To:Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date; bh=IjgAH4VnlnF8qNH+pcsQ61Fjj65cjZHCDuk+dLQlM1I=; b=MExmw7F+IlUs+wyKZqefZjPR5hbUw2ody4o85opFpOHyoEcUVfILKJOg5Nduweuighqv0aof6qhhLk9Ir4pnffsafr8QJc6hdBUBzPwGdZh8+iDYqnVsuZdTfbIk5580aYbW4W6qmO/JIFd0LLIGA2V4R6Br6K3uKx6sj11D1bI=; Received: from n2100.arm.linux.org.uk ([2001:4d48:ad52:3201:214:fdff:fe10:4f86]:35397) by pandora.arm.linux.org.uk with esmtpsa (TLSv1:DHE-RSA-AES256-SHA:256) (Exim 4.82_1-5b7a7c0-XX) (envelope-from ) id 1ZoZ7s-0004BE-8M; Tue, 20 Oct 2015 16:47:00 +0100 Received: from linux by n2100.arm.linux.org.uk with local (Exim 4.76) (envelope-from ) id 1ZoZ7o-0003oP-Ju; Tue, 20 Oct 2015 16:46:56 +0100 Date: Tue, 20 Oct 2015 16:46:56 +0100 From: Russell King - ARM Linux To: Geert Uytterhoeven Cc: Tomeu Vizoso , Mark Brown , Greg Kroah-Hartman , Rob Herring , Michael Turquette , Stephen Boyd , Vinod Koul , Dan Williams , Linus Walleij , Alexandre Courbot , Thierry Reding , David Airlie , Terje =?iso-8859-1?Q?Bergstr=F6m?= , Stephen Warren , Wolfram Sang , Frank Rowand , Grant Likely , Kishon Vijay Abraham I , Sebastian Reichel , Dmitry Eremin-Solenikov , David Woodhouse , Liam Girdwood , Felipe Balbi , Jingoo Han , Lee Jones , Jean-Christophe Plagniol-Villard , Tomi Valkeinen , "linux-kernel@vger.kernel.org" , linux-clk , dmaengine@vger.kernel.org, "linux-gpio@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-tegra@vger.kernel.org" , Linux I2C , "devicetree@vger.kernel.org" , "linux-pm@vger.kernel.org" , Linux PWM List , "linux-usb@vger.kernel.org" , Linux Fbdev development list Subject: Re: Alternative approach to solve the deferred probe (was: [GIT PULL] On-demand device probing) Message-ID: <20151020154656.GY32532@n2100.arm.linux.org.uk> References: <20151018192931.GY14956@sirena.org.uk> <20151018193757.GA9147@kroah.com> <20151018195330.GB14956@sirena.org.uk> <20151019131821.GA32532@n2100.arm.linux.org.uk> <20151019143045.GE32532@n2100.arm.linux.org.uk> <20151019153548.GM32532@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: dmaengine-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: dmaengine@vger.kernel.org X-Spam-Status: No, score=-6.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP On Mon, Oct 19, 2015 at 06:21:40PM +0200, Geert Uytterhoeven wrote: > Hi Russell, > > On Mon, Oct 19, 2015 at 5:35 PM, Russell King - ARM Linux > wrote: > >> > What you can do is print those devices which have failed to probe at > >> > late_initcall() time - possibly augmenting that with reports from > >> > subsystems showing what resources are not available, but that's only > >> > a guide, because of the "it might or might not be in a kernel module" > >> > problem. > >> > >> Well, adding those reports would give you a changelog similar to the > >> one in this series... > > > > I'm not sure about that, because what I was thinking of is adding > > a flag which would be set at late_initcall() time prior to running > > a final round of deferred device probing. > > Which round is the final round? > That's the one which didn't manage to bind any new devices to drivers, > which is something you only know _after_ the round has been run. > > So I think we need one extra round to handle this. > > > This flag would then be used in a deferred_warn() printk function > > which would normally be silent, but when this flag is set, it would > > print the reason for the deferral - and this would replace (or be > > added) to the subsystems and drivers which return -EPROBE_DEFER. > > > > That has the effect of hiding all the deferrals up until just before > > launching into userspace, which should then acomplish two things - > > firstly, getting rid of the rather useless deferred messages up to > > that point, and secondly printing the reason why the remaining > > deferrals are happening. > > > > That should be a small number of new lines plus a one-line change > > in subsystems and drivers. > > Apart from the extra round we probably can't get rid of, that sounds OK to me. Something like this. I haven't put a lot of effort into it to change all the places which return an -EPROBE_DEFER, and it also looks like we need some helpers to report when we have only an device_node (or should that be fwnode?) See the commented out of_warn_deferred() in drivers/gpio/gpiolib-of.c. Adding this stuff in the subsystems searching for resources should make debugging why things are getting deferred easier. We could make driver_deferred_probe_report something that can be deactivated again after the last deferred probe run, and provide the user with a knob that they can turn it back on again. I've tried this out on two of my platforms, including forcing driver_deferred_probe_report to be enabled, and I get exactly one deferred probe, so not a particularly good test. The patch won't apply as-is to mainline for all files; it's based on my tree which has some 360 additional patches (which seems to be about normal for my tree now.) drivers/base/dd.c | 29 +++++++++++++++++++++++++++++ drivers/base/power/domain.c | 7 +++++-- drivers/clk/clkdev.c | 9 ++++++++- drivers/gpio/gpiolib-of.c | 5 +++++ drivers/gpu/drm/bridge/dw_hdmi.c | 2 +- drivers/gpu/drm/exynos/exynos_drm_dsi.c | 2 +- drivers/gpu/drm/imx/imx-ldb.c | 5 +++-- drivers/gpu/drm/msm/dsi/dsi.c | 2 +- drivers/gpu/drm/msm/msm_drv.c | 3 ++- drivers/gpu/drm/rcar-du/rcar_du_crtc.c | 3 ++- drivers/of/irq.c | 5 ++++- drivers/pci/host/pci-mvebu.c | 1 + drivers/pinctrl/core.c | 5 +++-- drivers/pinctrl/devicetree.c | 4 ++-- drivers/regulator/core.c | 5 +++-- include/linux/device.h | 1 + 16 files changed, 71 insertions(+), 17 deletions(-) diff --git a/drivers/base/dd.c b/drivers/base/dd.c index be0eb4639128..bb12224f2901 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -129,7 +129,29 @@ void driver_deferred_probe_del(struct device *dev) mutex_unlock(&deferred_probe_mutex); } +static bool driver_deferred_probe_report; + +/** + * dev_warn_deferred() - report why a probe has been deferred + */ +void dev_warn_deferred(struct device *dev, const char *fmt, ...) +{ + if (driver_deferred_probe_report) { + struct va_format vaf; + va_list ap; + + va_start(ap, fmt); + vaf.fmt = fmt; + vaf.va = ≈ + + dev_warn(dev, "deferring probe: %pV", &vaf); + va_end(ap); + } +} +EXPORT_SYMBOL_GPL(dev_warn_deferred); + static bool driver_deferred_probe_enable = false; + /** * driver_deferred_probe_trigger() - Kick off re-probing deferred devices * @@ -188,6 +210,13 @@ static int deferred_probe_initcall(void) driver_deferred_probe_trigger(); /* Sort as many dependencies as possible before exiting initcalls */ flush_workqueue(deferred_wq); + + /* Now one final round, reporting any devices that remain deferred */ + driver_deferred_probe_report = true; + driver_deferred_probe_trigger(); + /* Sort as many dependencies as possible before exiting initcalls */ + flush_workqueue(deferred_wq); + return 0; } late_initcall(deferred_probe_initcall); diff --git a/drivers/base/power/domain.c b/drivers/base/power/domain.c index 16550c63d611..9f4d687d7268 100644 --- a/drivers/base/power/domain.c +++ b/drivers/base/power/domain.c @@ -1997,8 +1997,8 @@ int genpd_dev_pm_attach(struct device *dev) pd = of_genpd_get_from_provider(&pd_args); if (IS_ERR(pd)) { - dev_dbg(dev, "%s() failed to find PM domain: %ld\n", - __func__, PTR_ERR(pd)); + dev_warn_deferred(dev, "%s() failed to find PM domain: %ld\n", + __func__, PTR_ERR(pd)); of_node_put(dev->of_node); return -EPROBE_DEFER; } @@ -2026,6 +2026,9 @@ int genpd_dev_pm_attach(struct device *dev) ret = pm_genpd_poweron(pd); out: + if (ret) + dev_warn_deferred(dev, "%s() deferring probe: %d\n", + __func__, ret); return ret ? -EPROBE_DEFER : 0; } EXPORT_SYMBOL_GPL(genpd_dev_pm_attach); diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c index 779b6ff0c7ad..66f4212c63fd 100644 --- a/drivers/clk/clkdev.c +++ b/drivers/clk/clkdev.c @@ -201,7 +201,14 @@ struct clk *clk_get(struct device *dev, const char *con_id) if (dev) { clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id); - if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER) + if (IS_ERR(clk) && PTR_ERR(clk) == -EPROBE_DEFER) { + if (dev) + dev_warn_deferred(dev, + "unable to locate clock for connection %s\n", + con_id); + return clk; + } + if (!IS_ERR(clk)) return clk; } diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c index fa6e3c8823d6..36f09ab1c215 100644 --- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -101,6 +101,11 @@ struct gpio_desc *of_get_named_gpiod_flags(struct device_node *np, pr_debug("%s: parsed '%s' property of node '%s[%d]' - status (%d)\n", __func__, propname, np->full_name, index, PTR_ERR_OR_ZERO(gg_data.out_gpio)); + +// if (gg_data.out_gpio == -EPROBE_DEFER) +// of_warn_deferred(np, "%s: unable to locate GPIO for %s[%d]\n", +// __func__, propname, index); + return gg_data.out_gpio; } diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c index cb8764eecd70..088f5dd58424 100644 --- a/drivers/gpu/drm/bridge/dw_hdmi.c +++ b/drivers/gpu/drm/bridge/dw_hdmi.c @@ -1785,7 +1785,7 @@ int dw_hdmi_bind(struct device *dev, struct device *master, hdmi->ddc = of_find_i2c_adapter_by_node(ddc_node); of_node_put(ddc_node); if (!hdmi->ddc) { - dev_dbg(hdmi->dev, "failed to read ddc node\n"); + dev_warn_deferred(hdmi->dev, "failed to read ddc node\n"); return -EPROBE_DEFER; } diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c index 12b03b364703..3155798d8245 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c @@ -1899,7 +1899,7 @@ static int exynos_dsi_probe(struct platform_device *pdev) ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(dsi->supplies), dsi->supplies); if (ret) { - dev_info(dev, "failed to get regulators: %d\n", ret); + dev_warn_deferred(dev, "failed to get regulators: %d\n", ret); return -EPROBE_DEFER; } diff --git a/drivers/gpu/drm/imx/imx-ldb.c b/drivers/gpu/drm/imx/imx-ldb.c index abacc8f67469..0b57054c886a 100644 --- a/drivers/gpu/drm/imx/imx-ldb.c +++ b/drivers/gpu/drm/imx/imx-ldb.c @@ -595,8 +595,9 @@ static int imx_ldb_bind(struct device *dev, struct device *master, void *data) else return -EPROBE_DEFER; if (!channel->panel) { - dev_err(dev, "panel not found: %s\n", - remote->full_name); + dev_warn_deferred(dev, + "panel not found: %s\n", + remote->full_name); return -EPROBE_DEFER; } } diff --git a/drivers/gpu/drm/msm/dsi/dsi.c b/drivers/gpu/drm/msm/dsi/dsi.c index 6edcd6f57e70..3ba94a2bca65 100644 --- a/drivers/gpu/drm/msm/dsi/dsi.c +++ b/drivers/gpu/drm/msm/dsi/dsi.c @@ -42,7 +42,7 @@ static int dsi_get_phy(struct msm_dsi *msm_dsi) of_node_put(phy_node); if (!phy_pdev || !msm_dsi->phy) { - dev_err(&pdev->dev, "%s: phy driver is not ready\n", __func__); + dev_warn_deferred(&pdev->dev, "%s: phy driver is not ready\n", __func__); return -EPROBE_DEFER; } diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c index 0339c5d82d37..e1cfcd38c0dd 100644 --- a/drivers/gpu/drm/msm/msm_drv.c +++ b/drivers/gpu/drm/msm/msm_drv.c @@ -1117,7 +1117,8 @@ static int msm_pdev_probe(struct platform_device *pdev) dev = bus_find_device_by_name(&platform_bus_type, NULL, devnames[i]); if (!dev) { - dev_info(&pdev->dev, "still waiting for %s\n", devnames[i]); + dev_warn_deferred(&pdev->dev, "waiting for %s\n", + devnames[i]); return -EPROBE_DEFER; } diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c index 48cb19949ca3..bbf36f68d4e0 100644 --- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c +++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c @@ -600,7 +600,8 @@ int rcar_du_crtc_create(struct rcar_du_group *rgrp, unsigned int index) if (!IS_ERR(clk)) { rcrtc->extclock = clk; } else if (PTR_ERR(rcrtc->clock) == -EPROBE_DEFER) { - dev_info(rcdu->dev, "can't get external clock %u\n", index); + dev_warn_deferred(rcdu->dev, "can't get external clock %u\n", + index); return -EPROBE_DEFER; } diff --git a/drivers/of/irq.c b/drivers/of/irq.c index 55317fa9c9dc..2056bb9e4c43 100644 --- a/drivers/of/irq.c +++ b/drivers/of/irq.c @@ -404,8 +404,11 @@ int of_irq_get(struct device_node *dev, int index) return rc; domain = irq_find_host(oirq.np); - if (!domain) + if (!domain) { + dev_warn_deferred(dev, "%s() failed to locate IRQ domain\n", + __func__); return -EPROBE_DEFER; + } return irq_create_of_mapping(&oirq); } diff --git a/drivers/pci/host/pci-mvebu.c b/drivers/pci/host/pci-mvebu.c index 0e9b82095dc9..b49ae4822a5b 100644 --- a/drivers/pci/host/pci-mvebu.c +++ b/drivers/pci/host/pci-mvebu.c @@ -1203,6 +1203,7 @@ static int mvebu_pcie_parse_port(struct mvebu_pcie *pcie, reset_gpio = of_get_named_gpio_flags(child, "reset-gpios", 0, &flags); if (reset_gpio == -EPROBE_DEFER) { + dev_warn_deferred(dev, "unable to find reset gpio\n"); ret = reset_gpio; goto err; } diff --git a/drivers/pinctrl/core.c b/drivers/pinctrl/core.c index 9638a00c67c2..299aae3bca14 100644 --- a/drivers/pinctrl/core.c +++ b/drivers/pinctrl/core.c @@ -741,8 +741,9 @@ static int add_setting(struct pinctrl *p, struct pinctrl_map const *map) * OK let us guess that the driver is not there yet, and * let's defer obtaining this pinctrl handle to later... */ - dev_info(p->dev, "unknown pinctrl device %s in map entry, deferring probe", - map->ctrl_dev_name); + dev_warn_deferred(p->dev, + "unknown pinctrl device %s in map entry, deferring probe", + map->ctrl_dev_name); return -EPROBE_DEFER; } diff --git a/drivers/pinctrl/devicetree.c b/drivers/pinctrl/devicetree.c index fe04e748dfe4..358f946471c9 100644 --- a/drivers/pinctrl/devicetree.c +++ b/drivers/pinctrl/devicetree.c @@ -115,8 +115,8 @@ static int dt_to_map_one_config(struct pinctrl *p, const char *statename, for (;;) { np_pctldev = of_get_next_parent(np_pctldev); if (!np_pctldev || of_node_is_root(np_pctldev)) { - dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n", - np_config->full_name); + dev_warn_deferred(p->dev, "could not find pctldev for node %s, deferring probe\n", + np_config->full_name); of_node_put(np_pctldev); /* OK let's just assume this will appear later then */ return -EPROBE_DEFER; diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c index 8a34f6acc801..8d8ea0518283 100644 --- a/drivers/regulator/core.c +++ b/drivers/regulator/core.c @@ -1410,8 +1410,9 @@ static int regulator_resolve_supply(struct regulator_dev *rdev) if (have_full_constraints()) { r = dummy_regulator_rdev; } else { - dev_err(dev, "Failed to resolve %s-supply for %s\n", - rdev->supply_name, rdev->desc->name); + dev_warn_deferred(dev, + "Failed to resolve %s-supply for %s\n", + rdev->supply_name, rdev->desc->name); return -EPROBE_DEFER; } } diff --git a/include/linux/device.h b/include/linux/device.h index 5d7bc6349930..5050ce7d73b3 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -1087,6 +1087,7 @@ extern void device_shutdown(void); /* debugging and troubleshooting/diagnostic helpers. */ extern const char *dev_driver_string(const struct device *dev); +void dev_warn_deferred(struct device *dev, const char *fmt, ...); #ifdef CONFIG_PRINTK