From patchwork Tue Feb 1 17:47:32 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 12732099 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id AFF73C433FE for ; Tue, 1 Feb 2022 17:47:56 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id D311E10E4ED; Tue, 1 Feb 2022 17:47:51 +0000 (UTC) Received: from mail-wr1-x42a.google.com (mail-wr1-x42a.google.com [IPv6:2a00:1450:4864:20::42a]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1CBE410E469 for ; Tue, 1 Feb 2022 17:47:49 +0000 (UTC) Received: by mail-wr1-x42a.google.com with SMTP id w11so33472871wra.4 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=5d6AeaFTWdH/ja2uDiabv9TKllEUO3JegHiq5pGjkM8aLLcxaLBVt06np+ZSX7yW7q +RpHng1I8u1HnnqKjQ9VOlfcI9/1Jnn+VvG9hBpwoSdKWjeduTgTDFhWirmtRQ1rpCCh EXlVD3XbBs4aVApo2VmMeNAXysE9cWncjj5qEXctVC9kO2VqXg0/UfrNBpTQF5rzPTnm m+/bEtHkDWha0lJJ3JfLoRbUbL38x4V16CnAnqXMYBeYV/xsBF0DIZq29l03M1urusqh 50oR+tptqvIJSwMbBkVyfBAJCYfu57+MUJu8cz4vWxo1xMBwHq1cK7KRR1HF/jK6Jk7N hCyQ== X-Gm-Message-State: AOAM53028gOdnHCmQF43SHUPZd0dlnaDda32GmPhOeB9LKmamHzjQVVJ 3NBeOh8sfs8B/nKVJGHn9+2Ebg== 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 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 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Thompson , David Airlie , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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/dsi_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) /* do not autoenable, will be enabled later */ ret = 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", From patchwork Tue Feb 1 17:47:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Daniel Thompson X-Patchwork-Id: 12732098 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 4372AC433F5 for ; Tue, 1 Feb 2022 17:47:54 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id B5D0A10E4E0; Tue, 1 Feb 2022 17:47:51 +0000 (UTC) Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by gabe.freedesktop.org (Postfix) with ESMTPS id 2F1DC10E1B7 for ; Tue, 1 Feb 2022 17:47:50 +0000 (UTC) Received: by mail-wr1-x42b.google.com with SMTP id l25so33416338wrb.13 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=uWs49JHExRR+0R48j+6q5l9fivPldgpmiuvwKap4mYPpsEvC8v0NKNGOhH0YyEZPwh eusDY7rdtvGkmOKCgHAOs0NPLIr+OAIzNmDG8/y+FffGYSr0jMxoc4c4b2BwwPQB/KaK +RpMXASKsSp2F/ihIUFF4UGPH1eHMzSHgz22Gq5K3cjqm6j0oe5UP+Oij0mtZ8Maq7Bm TDCL/pYBABpkZi97LVPdpXoo+2i7uvaOGHLaPpv125V4yHJCawaxhZFYdhdDYdxTuALp IyJOV1OdOu6ib5ZOIejfVGzj/qRT2PJOQELyuMfdCE/n3kbpjP3ijJTNDRYEpC9FW6lP f2gQ== X-Gm-Message-State: AOAM533UEy1LqN2ioxZF49CyGDmt/qUuanSbd+XBjkZOXJllfoOiIRr3 EjjI96oG4OyK2wqfd0jIhLQO7nCHHBhfyhgr 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 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 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Daniel Thompson , David Airlie , linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" 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 Reviewed-by: Dmitry Baryshkov --- 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/hdmi.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, } ret = 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",