From nobody Mon Jun 29 22:12:27 2026 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 E4986C433EF for ; Tue, 1 Feb 2022 17:47:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241691AbiBARr4 (ORCPT ); Tue, 1 Feb 2022 12:47:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43072 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241736AbiBARrt (ORCPT ); Tue, 1 Feb 2022 12:47:49 -0500 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1BBE3C061714 for ; Tue, 1 Feb 2022 09:47:49 -0800 (PST) Received: by mail-wr1-x432.google.com with SMTP id k18so33554670wrg.11 for ; Tue, 01 Feb 2022 09:47:49 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=R75JAp3M1abKRfmniOJ5Fuzudqh5/VKktmnzYEpT+SA=; b=oc9p+IVnBHLB7LZf1r+Ni3OD5gI1bzBxGsS5LT4cHBQaWFBb8jmm09tcie0gM8UUXm ibm81fKzJqBSY+FMLvG73EWI84K2BM1YX13xch+ZfGy/lkyDQmUlKPdd5ATMe4tP2qAY q2LLC47PesQHEdn+4fhjytGJiJ8lZaxKwWYKNVKC7mTuna62YxR4MvheG0z2k8wcTm5P y4irdy/vhh7Ze/iNid4lRN7TC6PRVv/3sRnZvxcMK59xmIrHUgLW9gCH7CvxL5r6bJsZ 846qFCxExqndxRykCeG3S3C3H6tO3V8aBmYYve9TYbeFxWYiQ4I32VVGSXqXVIdVuoOC Tc3g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=R75JAp3M1abKRfmniOJ5Fuzudqh5/VKktmnzYEpT+SA=; b=c+NJ0Yra9PHrGfd55lhBy2oQ9CzkR3S/xkjsSLmhROtplGBwEalWhEYw+9wjNYFaJ3 aHm2ccikOH9ZmNOWSRsxSSzt730U0vk36T78+ZDL/jJKaR7fcgPF+qNIPseU5ShG6Wul MXlSTihUyqmvhbMynkXsX7Y6lk0YNfrji+PICPSpW9YDnP87WsJ4ZLzcL8xiiwAAZ3bB AZqNaPEBpvOcZHymgcYdFRupKaJtFWSknUTQRQ7GR7dy6GnQ32191O/u8S0LB5aKZbHN JnI3vQe84hDXt6ibADCEX7sUTfSEbOUQzLGzfisN+VScNX4d73+JKhvrh4FvrZMbwArW 26tg== X-Gm-Message-State: AOAM530gzIzhrVNT5RynBm2BxyNNSpe1LP2Le5bx5GGydZLhgThu6GRA JdsKVIwWVPzvppecqCV+Iuy/eg== X-Google-Smtp-Source: ABdhPJz+0uF1t9U/iG6eoJW1NBuaJp+mrqnVdnHAzVxmlbZS8+iIV8r1hEW+Y3SrEIxDg2ACIbSF1Q== X-Received: by 2002:adf:f141:: with SMTP id y1mr22073899wro.104.1643737667624; Tue, 01 Feb 2022 09:47:47 -0800 (PST) Received: from maple.lan (cpc141216-aztw34-2-0-cust174.18-1.cable.virginm.net. [80.7.220.175]) by smtp.gmail.com with ESMTPSA id r2sm3392332wmq.24.2022.02.01.09.47.46 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Feb 2022 09:47:47 -0800 (PST) From: Daniel Thompson To: Rob Clark , Sean Paul , Abhinav Kumar Cc: Daniel Thompson , David Airlie , Daniel Vetter , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/2] drm/msm/dsi: Remove spurious IRQF_ONESHOT flag Date: Tue, 1 Feb 2022 17:47:32 +0000 Message-Id: <20220201174734.196718-2-daniel.thompson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220201174734.196718-1-daniel.thompson@linaro.org> References: <20220201174734.196718-1-daniel.thompson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Quoting the header comments, IRQF_ONESHOT is "Used by threaded interrupts which need to keep the irq line disabled until the threaded handler has been run.". When applied to an interrupt that doesn't request a threaded irq then IRQF_ONESHOT has a lesser known (undocumented?) side effect, which it to disable the forced threading of irqs (and for "normal" kernels it is a nop). In this case I can find no evidence that suppressing forced threading is intentional. Had it been intentional then a driver must adopt the raw_spinlock API in order to avoid deadlocks on PREEMPT_RT kernels (and avoid calling any kernel API that uses regular spinlocks). Fix this by removing the spurious additional flag. This change is required for my Snapdragon 7cx Gen2 tablet to boot-to-GUI with PREEMPT_RT enabled. Signed-off-by: Daniel Thompson Reviewed-by: Dmitry Baryshkov --- drivers/gpu/drm/msm/dsi/dsi_host.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/d= si_host.c index 6b3ced4aaaf5d..3a3f53f0c8ae1 100644 --- a/drivers/gpu/drm/msm/dsi/dsi_host.c +++ b/drivers/gpu/drm/msm/dsi/dsi_host.c @@ -1877,7 +1877,7 @@ int msm_dsi_host_init(struct msm_dsi *msm_dsi) =20 /* do not autoenable, will be enabled later */ ret =3D devm_request_irq(&pdev->dev, msm_host->irq, dsi_host_irq, - IRQF_TRIGGER_HIGH | IRQF_ONESHOT | IRQF_NO_AUTOEN, + IRQF_TRIGGER_HIGH | IRQF_NO_AUTOEN, "dsi_isr", msm_host); if (ret < 0) { dev_err(&pdev->dev, "failed to request IRQ%u: %d\n", --=20 2.34.1 From nobody Mon Jun 29 22:12:27 2026 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 20450C433F5 for ; Tue, 1 Feb 2022 17:47:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241706AbiBARr5 (ORCPT ); Tue, 1 Feb 2022 12:47:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43080 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241747AbiBARru (ORCPT ); Tue, 1 Feb 2022 12:47:50 -0500 Received: from mail-wr1-x432.google.com (mail-wr1-x432.google.com [IPv6:2a00:1450:4864:20::432]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 27A6FC061714 for ; Tue, 1 Feb 2022 09:47:50 -0800 (PST) Received: by mail-wr1-x432.google.com with SMTP id u15so33549581wrt.3 for ; Tue, 01 Feb 2022 09:47:50 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=7TPcuWXxFU6hWv6NeLAOie1udRWkhLJ1DWe5t2FsQ+M=; b=NuDwlgu6ILp+04FQNgBAsUPzgY4AJ4bWp5fA+81vgbrR5oDX2XCAO6zFTyz1N6KBkU 1kdQkH85xpE2ggU6G7YOsyHHkTToqT8hEBjk5z4lr12RD7yj4VqBh0sdrZL5PnVifknW 4Yd8p3bHKpvTFcIiHl+wEjbshC1kHaYl4TwJhUINoU5P7+NT6/c0K3F2jcQT7LSNe9yy FaXvEgb0ZLMnKx8Bk9pyEz77Z7+wYBdKtsrkqcuuKGXhgjKJySsryv8ltvb/6sadloTy UzkbJtcaH9lrLMA/LhpmdFsKm7icqg8TsZuhhQDF0expi5wKdSPQ3x9ySEnfmKNh7Pkn ccBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=7TPcuWXxFU6hWv6NeLAOie1udRWkhLJ1DWe5t2FsQ+M=; b=WqixQdAHfM6MYvF9949/whJQHSiV4Upa5d+xI53F1NeTOpRhoV9rJAcSfnGVM3su8U acs4MSpiqXULKnN4e79uOIWVoqCqohUBgClg2oghiJLeobQGF8cEayGRLKGPLLtXn7jq V38g49/kJ/wTCZHl8rXnVBaxetkY0d+GflN7GTQTFy9NiI7VkEbCyQ0k12dS90OyRu7k Br0HtvIP5RhYX1Wr/n2Jgqwr8+utl89yfuHCq/iKva/WTWcrDew21RoRoVLV5TphD4G+ 4dhVwcTGyVauxz4m4YXbEKXI2bQfkfoNMpTsivG0ASbESMH2wCEe1ZnWiBMjpgogubdY jrDA== X-Gm-Message-State: AOAM530M7et9sLwMR353TKw+EVOwutkHVtn9n/HcyAGnA5tgnTBp13d4 jiswmqr5AjaU2omjwyfsRX6vMw== X-Google-Smtp-Source: ABdhPJwDJNj1YVlHWPoJ293olzLjFEIQcMbpGy6i0JMKcmYgnDUgr1EqX8iuwkgOa1W/rpbnq/zJPg== X-Received: by 2002:a05:6000:1548:: with SMTP id 8mr21586066wry.504.1643737668657; Tue, 01 Feb 2022 09:47:48 -0800 (PST) Received: from maple.lan (cpc141216-aztw34-2-0-cust174.18-1.cable.virginm.net. [80.7.220.175]) by smtp.gmail.com with ESMTPSA id r2sm3392332wmq.24.2022.02.01.09.47.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 01 Feb 2022 09:47:48 -0800 (PST) From: Daniel Thompson To: Rob Clark , Sean Paul , Abhinav Kumar Cc: Daniel Thompson , David Airlie , Daniel Vetter , linux-arm-msm@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] drm/msm/hdmi: Remove spurious IRQF_ONESHOT flag Date: Tue, 1 Feb 2022 17:47:33 +0000 Message-Id: <20220201174734.196718-3-daniel.thompson@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20220201174734.196718-1-daniel.thompson@linaro.org> References: <20220201174734.196718-1-daniel.thompson@linaro.org> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Quoting the header comments, IRQF_ONESHOT is "Used by threaded interrupts which need to keep the irq line disabled until the threaded handler has been run.". When applied to an interrupt that doesn't request a threaded irq then IRQF_ONESHOT has a lesser known (undocumented?) side effect, which it to disable the forced threading of irqs. For "normal" kernels if there is no thread_fn then IRQF_ONESHOT is a nop. In this case disabling forced threading is not appropriate because the driver calls wake_up_all() (via msm_hdmi_i2c_irq) and also directly uses the regular spinlock API for locking (in msm_hdmi_hdcp_irq() ). Neither of these APIs can be called from no-thread interrupt handlers on PREEMPT_RT systems. Fix this by removing IRQF_ONESHOT. Signed-off-by: Daniel Thompson --- drivers/gpu/drm/msm/hdmi/hdmi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/hdmi/hdmi.c b/drivers/gpu/drm/msm/hdmi/hdm= i.c index 719720709e9e7..e167817b42958 100644 --- a/drivers/gpu/drm/msm/hdmi/hdmi.c +++ b/drivers/gpu/drm/msm/hdmi/hdmi.c @@ -306,7 +306,7 @@ int msm_hdmi_modeset_init(struct hdmi *hdmi, } =20 ret =3D devm_request_irq(&pdev->dev, hdmi->irq, - msm_hdmi_irq, IRQF_TRIGGER_HIGH | IRQF_ONESHOT, + msm_hdmi_irq, IRQF_TRIGGER_HIGH, "hdmi_isr", hdmi); if (ret < 0) { DRM_DEV_ERROR(dev->dev, "failed to request IRQ%u: %d\n", --=20 2.34.1