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 7D0D3C46467 for ; Mon, 16 Jan 2023 16:05:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232009AbjAPQFV (ORCPT ); Mon, 16 Jan 2023 11:05:21 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45068 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232202AbjAPQE6 (ORCPT ); Mon, 16 Jan 2023 11:04:58 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5183A24113 for ; Mon, 16 Jan 2023 08:03:21 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id E2A9961031 for ; Mon, 16 Jan 2023 16:03:20 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0161AC433D2; Mon, 16 Jan 2023 16:03:19 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673885000; bh=JGlEy+4M/1OZTo0zHsn1ym9DVZMv4jzdVZX6Eu4KR+k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=wNiNNqZNoKbqtRtw4/TykL3wMU9N8rfEZ9PBXrbQLv/NwS6ZbgcXfvCPo1Cu4iNBE lvXCJJhkuq1jm79alebq2n+NNl0QevEIlAOQpB9POvJyqt8+7YDoI4G0ijh7kBNSzA 2h1AutTYR7Ab+WTepnlZ6ooJipfIbpeQm1cXjLhU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Kuogee Hsieh , Douglas Anderson , Abhinav Kumar , Dmitry Baryshkov Subject: [PATCH 5.15 29/86] drm/msm/dp: do not complete dp_aux_cmd_fifo_tx() if irq is not for aux transfer Date: Mon, 16 Jan 2023 16:51:03 +0100 Message-Id: <20230116154748.311325665@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230116154747.036911298@linuxfoundation.org> References: <20230116154747.036911298@linuxfoundation.org> User-Agent: quilt/0.67 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Kuogee Hsieh commit 1cba0d150fa102439114a91b3e215909efc9f169 upstream. There are 3 possible interrupt sources are handled by DP controller, HPDstatus, Controller state changes and Aux read/write transaction. At every irq, DP controller have to check isr status of every interrupt sources and service the interrupt if its isr status bits shows interrupts are pending. There is potential race condition may happen at current aux isr handler implementation since it is always complete dp_aux_cmd_fifo_tx() even irq is not for aux read or write transaction. This may cause aux read transaction return premature if host aux data read is in the middle of waiting for sink to complete transferring data to host while irq happen. This will cause host's receiving buffer contains unexpected data. This patch fixes this problem by checking aux isr and return immediately at aux isr handler if there are no any isr status bits set. Current there is a bug report regrading eDP edid corruption happen during system booting up. After lengthy debugging to found that VIDEO_READY interrupt was continuously firing during system booting up which cause dp_aux_isr() to complete dp_aux_cmd_fifo_tx() prematurely to retrieve data from aux hardware buffer which is not yet contains complete data transfer from sink. This cause edid corruption. Follows are the signature at kernel logs when problem happen, EDID has corrupt header panel-simple-dp-aux aux-aea0000.edp: Couldn't identify panel via EDID Changes in v2: -- do complete if (ret == IRQ_HANDLED) ay dp-aux_isr() -- add more commit text Changes in v3: -- add Stephen suggested -- dp_aux_isr() return IRQ_XXX back to caller -- dp_ctrl_isr() return IRQ_XXX back to caller Changes in v4: -- split into two patches Changes in v5: -- delete empty line between tags Changes in v6: -- remove extra "that" and fixed line more than 75 char at commit text Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Signed-off-by: Kuogee Hsieh Tested-by: Douglas Anderson Reviewed-by: Abhinav Kumar Reviewed-by: Dmitry Baryshkov Patchwork: https://patchwork.freedesktop.org/patch/516121/ Link: https://lore.kernel.org/r/1672193785-11003-2-git-send-email-quic_khsieh@quicinc.com Signed-off-by: Abhinav Kumar Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/msm/dp/dp_aux.c | 4 ++++ 1 file changed, 4 insertions(+) --- a/drivers/gpu/drm/msm/dp/dp_aux.c +++ b/drivers/gpu/drm/msm/dp/dp_aux.c @@ -406,6 +406,10 @@ void dp_aux_isr(struct drm_dp_aux *dp_au isr = dp_catalog_aux_get_irq(aux->catalog); + /* no interrupts pending, return immediately */ + if (!isr) + return; + if (!aux->cmd_busy) return;