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 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: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- 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", -- 2.34.1