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 X-Spam-Level: X-Spam-Status: No, score=-8.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2F9DEC433B4 for ; Wed, 19 May 2021 16:01:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 021E86109F for ; Wed, 19 May 2021 16:01:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347000AbhESQC7 (ORCPT ); Wed, 19 May 2021 12:02:59 -0400 Received: from so254-9.mailgun.net ([198.61.254.9]:32585 "EHLO so254-9.mailgun.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346958AbhESQC6 (ORCPT ); Wed, 19 May 2021 12:02:58 -0400 DKIM-Signature: a=rsa-sha256; v=1; c=relaxed/relaxed; d=mg.codeaurora.org; q=dns/txt; s=smtp; t=1621440098; h=Message-ID: References: In-Reply-To: Subject: Cc: To: From: Date: Content-Transfer-Encoding: Content-Type: MIME-Version: Sender; bh=f3esNVJWkyreSf7lUucLsVmFEpcwPaQNQn4DlkwCpPk=; b=VABrDoTamNhNVNOldPPkY2CSmyNNwECRYvmHAjyUCiB9sGsM3UD2C6VM7eRtKrtETCaOlnGT w8U1pEj1rmc9ZqdEmSBv6oHoU4qNAs+ndG4twvRDT4IOpuqrUNrwcjjDZ2FOr6OfpLCmZCfX W51EK8sDIGiLnTRbt/kjhAIXOQ8= X-Mailgun-Sending-Ip: 198.61.254.9 X-Mailgun-Sid: WyI1MzIzYiIsICJsaW51eC1hcm0tbXNtQHZnZXIua2VybmVsLm9yZyIsICJiZTllNGEiXQ== Received: from smtp.codeaurora.org (ec2-35-166-182-171.us-west-2.compute.amazonaws.com [35.166.182.171]) by smtp-out-n04.prod.us-east-1.postgun.com with SMTP id 60a5363fb15734c8f97708f1 (version=TLS1.2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256); Wed, 19 May 2021 16:01:03 GMT Sender: khsieh=codeaurora.org@mg.codeaurora.org Received: by smtp.codeaurora.org (Postfix, from userid 1001) id 08D2AC4323A; Wed, 19 May 2021 16:01:02 +0000 (UTC) Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) (Authenticated sender: khsieh) by smtp.codeaurora.org (Postfix) with ESMTPSA id 34CC2C433F1; Wed, 19 May 2021 16:01:02 +0000 (UTC) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 19 May 2021 09:01:02 -0700 From: khsieh@codeaurora.org To: Stephen Boyd Cc: agross@kernel.org, bjorn.andersson@linaro.org, robdclark@gmail.com, sean@poorly.run, vkoul@kernel.org, abhinavk@codeaurora.org, aravindh@codeaurora.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v4 1/2] drm/msm/dp: handle irq_hpd with sink_count = 0 correctly In-Reply-To: References: <1621013713-6860-1-git-send-email-khsieh@codeaurora.org> Message-ID: X-Sender: khsieh@codeaurora.org User-Agent: Roundcube Webmail/1.3.9 Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 2021-05-18 14:42, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2021-05-14 10:35:13) >> irq_hpd interrupt should be handled after dongle plugged in and >> before dongle unplugged. Hence irq_hpd interrupt is enabled at >> the end of the plugin handle and disabled at the beginning of >> unplugged handle. Current irq_hpd with sink_count = 0 is wrongly >> handled same as the dongle unplugged which tears down the mainlink >> and disables the phy. This patch fixes this problem by only tearing >> down the mainlink but keeping phy enabled at irq_hpd with >> sink_count = 0 handle so that next irq_hpd with sink_count =1 can be >> handled by setup mainlink only. >> >> Changes in v2: >> -- add ctrl->phy_Power_count >> >> Changes in v3: >> -- del ctrl->phy_Power_count >> -- add phy_power_off to dp_ctrl_off_link_stream() >> >> Changes in v4: >> -- return immediately if clock disable failed at >> dp_ctrl_off_link_stream() >> >> Signed-off-by: Kuogee Hsieh > > I think we want some Fixes tag. Not sure what it would be though. > > I also noticed that if I plug and unplug the HDMI cable from my apple > dongle that I see this error message > > [drm:dp_display_usbpd_attention_cb] *ERROR* Disconnected, no > DP_LINK_STATUS_UPDATED > *ERROR* Disconnected, no DP_LINK_STATUS_UPDATED <== this is caused by > dongle generate the second irq_hpd with sink_count = 0 after first first irq_hpd with sink_count = 0. The fix is you have set dongle to D3 (power off) state after first irq_pd with sink_count = 0 handled. I have a patch fix this problem. I will merge and re submit for review. > which looks like the irq_hpd comes in while I'm disconnecting the HDMI > cable but the hpd_state is ST_DISCONNECTED. The state is set to > ST_DISCONNECTED in msm_dp_display_disable() so it seems that userspace > has turned off the external display, and then the kthread runs for the > irq_hpd but it's too late. > > Something is missing from this patch then to properly disable the > IRQ_HPD interrupt before telling userspace that the external display is > disconnected. Shouldn't we be toggling the irq enable bits from the > hardirq context when we figure out what it is? The logic would be > > in_hardirq() { > > if (hpd high) > enable_irq_hpd(); // Probably this can be delayed to the kthread > after enabling the link > > if (hpd_low) > disable_irq_hpd(); // But this certainly cannot be in the kthread > > else if (irq_hpd) // Notice the else-if so that if hpd is low we > don't even try to handle irq_hpd if it came in at the same time > handle_irq_hpd(); > } > > Because we can't really mess with the irq controls in the kthread when > hpd goes low, it will be too late. For all we know, the kthread could > run seconds later, after an irq_hpd has come bouncing in at the same > time and pushed an irq_hpd handling event onto the kthread.