From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0F572469F for ; Mon, 28 Aug 2023 10:34:13 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88245C433C9; Mon, 28 Aug 2023 10:34:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1693218852; bh=eU+j5+XOpPEeoE5JwLvS80YN/aOWbk7CZ9mNbMMhKOk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=FqLM6NCyaSsVGfMkP4Jpr66oEj9HbDhDBFOSPL/1Z4jeZkTeH1E3txDQnQxT2HseF zp9/LKIMfrerPk7AXBNViDtSNqcXaidPYuhiWLoWUb0BebUxBagZi0I+Cd5rw3cBus 01Q8W//tPYnI/yyieHtC5tO5vSACcQVYL48LQVFo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Sanath S , Sanjay R Mehta , Mika Westerberg , Mario Limonciello Subject: [PATCH 6.1 107/122] thunderbolt: Fix Thunderbolt 3 display flickering issue on 2nd hot plug onwards Date: Mon, 28 Aug 2023 12:13:42 +0200 Message-ID: <20230828101159.980699717@linuxfoundation.org> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20230828101156.480754469@linuxfoundation.org> References: <20230828101156.480754469@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Sanjay R Mehta commit 583893a66d731f5da010a3fa38a0460e05f0149b upstream. Previously, on unplug events, the TMU mode was disabled first followed by the Time Synchronization Handshake, irrespective of whether the tb_switch_tmu_rate_write() API was successful or not. However, this caused a problem with Thunderbolt 3 (TBT3) devices, as the TSPacketInterval bits were always enabled by default, leading the host router to assume that the device router's TMU was already enabled and preventing it from initiating the Time Synchronization Handshake. As a result, TBT3 monitors experienced display flickering from the second hot plug onwards. To address this issue, we have modified the code to only disable the Time Synchronization Handshake during TMU disable if the tb_switch_tmu_rate_write() function is successful. This ensures that the TBT3 devices function correctly and eliminates the display flickering issue. Co-developed-by: Sanath S Signed-off-by: Sanath S Signed-off-by: Sanjay R Mehta Cc: stable@vger.kernel.org Signed-off-by: Mika Westerberg [ USB4v2 introduced support for uni-directional TMU mode as part of d49b4f043d63 ("thunderbolt: Add support for enhanced uni-directional TMU mode") This is not a stable candidate commit, so adjust the code for backport. ] Signed-off-by: Mario Limonciello Signed-off-by: Greg Kroah-Hartman --- drivers/thunderbolt/tmu.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/drivers/thunderbolt/tmu.c +++ b/drivers/thunderbolt/tmu.c @@ -415,7 +415,8 @@ int tb_switch_tmu_disable(struct tb_swit * uni-directional mode and we don't want to change it's TMU * mode. */ - tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF); + ret = tb_switch_tmu_rate_write(sw, TB_SWITCH_TMU_RATE_OFF); + return ret; tb_port_tmu_time_sync_disable(up); ret = tb_port_tmu_time_sync_disable(down);