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 D21EC1C29 for ; Wed, 23 Nov 2022 09:40:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 34D85C433C1; Wed, 23 Nov 2022 09:40:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1669196431; bh=A2xAvQbnLCqr8nWJbVANHA9l03LHWAGNYIoynTr8tk8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=GcQg1jEsLSKM8WVGjTa/dbxYrWAgZ2rLGh2LY3QDqZTc56t4a+70/BHiQXRwbgxyt YgLVDtAyQ8M5okLvOaw9Mj/hj5cIq+/VPAl90HiDmeIVkMqIXdALftlZ5KxIYnwY5g VC2uh8JiE06GY2mZSaFagfWCXXQiGSG9uuFh7NkI= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Daniel Wheeler , Qingqing Zhuo , Rodrigo Siqueira , Alex Deucher , Sasha Levin Subject: [PATCH 6.0 028/314] drm/amd/display: Remove wrong pipe control lock Date: Wed, 23 Nov 2022 09:47:53 +0100 Message-Id: <20221123084626.788138592@linuxfoundation.org> X-Mailer: git-send-email 2.38.1 In-Reply-To: <20221123084625.457073469@linuxfoundation.org> References: <20221123084625.457073469@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Rodrigo Siqueira [ Upstream commit ca08a1725d0d78efca8d2dbdbce5ea70355da0f2 ] When using a device based on DCN32/321, we have an issue where a second 4k@60Hz display does not light up, and the system becomes unresponsive for a few minutes. In the debug process, it was possible to see a hang in the function dcn20_post_unlock_program_front_end in this part: for (j = 0; j < TIMEOUT_FOR_PIPE_ENABLE_MS*1000 && hubp->funcs->hubp_is_flip_pending(hubp); j++) mdelay(1); } The hubp_is_flip_pending always returns positive for waiting pending flips which is a symptom of pipe hang. Additionally, the dmesg log shows this message after a few minutes: BUG: soft lockup - CPU#4 stuck for 26s! ... [ +0.000003] dcn20_post_unlock_program_front_end+0x112/0x340 [amdgpu] [ +0.000171] dc_commit_state_no_check+0x63d/0xbf0 [amdgpu] [ +0.000155] ? dc_validate_global_state+0x358/0x3d0 [amdgpu] [ +0.000154] dc_commit_state+0xe2/0xf0 [amdgpu] This confirmed the hypothesis that we had a pipe hanging somewhere. Next, after checking the ftrace entries, we have the below weird sequence: [..] 2) | dcn10_lock_all_pipes [amdgpu]() { 2) 0.120 us | optc1_is_tg_enabled [amdgpu](); 2) | dcn20_pipe_control_lock [amdgpu]() { 2) | dc_dmub_srv_clear_inbox0_ack [amdgpu]() { 2) 0.121 us | amdgpu_dm_dmub_reg_write [amdgpu](); 2) 0.551 us | } 2) | dc_dmub_srv_send_inbox0_cmd [amdgpu]() { 2) 0.110 us | amdgpu_dm_dmub_reg_write [amdgpu](); 2) 0.511 us | } 2) | dc_dmub_srv_wait_for_inbox0_ack [amdgpu]() { 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); 2) 0.110 us | amdgpu_dm_dmub_reg_read [amdgpu](); [..] We are not expected to read from dmub register so many times and for so long. From the trace log, it was possible to identify that the function dcn20_pipe_control_lock was triggering the dmub operation when it was unnecessary and causing the hang issue. This commit drops the unnecessary dmub code and, consequently, fixes the second display not lighting up the issue. Tested-by: Daniel Wheeler Acked-by: Qingqing Zhuo Signed-off-by: Rodrigo Siqueira Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c | 12 +----------- 1 file changed, 1 insertion(+), 11 deletions(-) diff --git a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c index 598ce872a8d7..0f30df523fdf 100644 --- a/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c +++ b/drivers/gpu/drm/amd/display/dc/dcn20/dcn20_hwseq.c @@ -1262,16 +1262,6 @@ void dcn20_pipe_control_lock( lock, &hw_locks, &inst_flags); - } else if (pipe->stream && pipe->stream->mall_stream_config.type == SUBVP_MAIN) { - union dmub_inbox0_cmd_lock_hw hw_lock_cmd = { 0 }; - hw_lock_cmd.bits.command_code = DMUB_INBOX0_CMD__HW_LOCK; - hw_lock_cmd.bits.hw_lock_client = HW_LOCK_CLIENT_DRIVER; - hw_lock_cmd.bits.lock_pipe = 1; - hw_lock_cmd.bits.otg_inst = pipe->stream_res.tg->inst; - hw_lock_cmd.bits.lock = lock; - if (!lock) - hw_lock_cmd.bits.should_release = 1; - dmub_hw_lock_mgr_inbox0_cmd(dc->ctx->dmub_srv, hw_lock_cmd); } else if (pipe->plane_state != NULL && pipe->plane_state->triplebuffer_flips) { if (lock) pipe->stream_res.tg->funcs->triplebuffer_lock(pipe->stream_res.tg); @@ -1848,7 +1838,7 @@ void dcn20_post_unlock_program_front_end( for (j = 0; j < TIMEOUT_FOR_PIPE_ENABLE_MS*1000 && hubp->funcs->hubp_is_flip_pending(hubp); j++) - mdelay(1); + udelay(1); } } -- 2.35.1