From patchwork Wed Mar 13 00:13:16 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 13590784 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 344ECC54E58 for ; Wed, 13 Mar 2024 00:14:04 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 3419610F270; Wed, 13 Mar 2024 00:14:02 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=chromium.org header.i=@chromium.org header.b="DINkFzr1"; dkim-atps=neutral Received: from mail-pl1-f172.google.com (mail-pl1-f172.google.com [209.85.214.172]) by gabe.freedesktop.org (Postfix) with ESMTPS id 958A510F3E5 for ; Wed, 13 Mar 2024 00:13:59 +0000 (UTC) Received: by mail-pl1-f172.google.com with SMTP id d9443c01a7336-1dc29f1956cso31473275ad.0 for ; Tue, 12 Mar 2024 17:13:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; t=1710288839; x=1710893639; darn=lists.freedesktop.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=iH7dOzHfySID1hx+dQROG4kWo57xV6ZLxO4hN1el+Bw=; b=DINkFzr10zz9XeI0XcObB4nKr/4njoJ21H1TU+beotMEN15KpWrfD2qXsJciFjjVnj STsnkzVLJKrdJAAUvrNGxZhKLiF/X7VBLqKTGgWCSPW6msPfdQDuxpPvSjfJUamYl84p 3uEhPlK+OIZZXnugeg1+DJwtJN8IV2M4HHgxY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1710288839; x=1710893639; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=iH7dOzHfySID1hx+dQROG4kWo57xV6ZLxO4hN1el+Bw=; b=NTopqRxhw/SXQA+S5tEiWbFGwYVD5WE2Q3qfYRefryUicb5qm2Rgr71B3ZCtdRfuES XwLIZFOXZigkafaRcSF5643c49A0Wqy8nbU6SR/QmiBreSSs/Sj1EZa+T0QhEdI3c2wM 9YYa1TUMwzs21hgvVdPAX3au7E/nIbY84TAg8TI/2tLp2gIjkKfXVLtMDsXfZ3FUm/RF RXUHcgfhDQINq4uwXqcQMuCkn7Ghc8vWEYLlLxk1qfuwMw3RR3cDNMT/hpNZ5e6VzoiP dY94rvzMF2t4BnbODBC1BTCyoTzkZTbpL0D4RqN4nDa4+5fGEt7XtfwUYglqDDSuodbw la0g== X-Forwarded-Encrypted: i=1; AJvYcCUToatp9m85AVXJgE+8voVrOUzIRst4iToCJem27qtWPY9ZZjR9mtromXc0vNdJLSlbe8er+wIeR3zP9Q1G/XXCmB7W2NOaFQV869RAI1tV X-Gm-Message-State: AOJu0YznOeHdQXiJqFjUw1vVP2sZzxWmDkj7eHxR+OI96bAjedJDIXBT EY4W/+FNqBeyFqGwrowx3OurR0Gje0Zjhk9hrSu5K2atad0UpJv5UYwzFyYmTg== X-Google-Smtp-Source: AGHT+IF8TBuICwc1/oaTRuDykpJ3M8i0pZiDCaxf+rAiL5WJKMEjNtGSI5raH9YjmvsuRaXg9/0jPg== X-Received: by 2002:a17:902:cec1:b0:1dd:a16e:dea4 with SMTP id d1-20020a170902cec100b001dda16edea4mr8173646plg.67.1710288839081; Tue, 12 Mar 2024 17:13:59 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2620:15c:9d:2:f8dd:895c:e876:6edb]) by smtp.gmail.com with ESMTPSA id x8-20020a170902a38800b001dd761faec3sm7432924pla.251.2024.03.12.17.13.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Mar 2024 17:13:57 -0700 (PDT) From: Douglas Anderson To: Rob Clark , Abhinav Kumar , Dmitry Baryshkov Cc: Douglas Anderson , Bjorn Andersson , Daniel Vetter , David Airlie , Guenter Roeck , Kuogee Hsieh , Marijn Suijten , Sean Paul , Tanmay Shah , Vinod Polimera , dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 1/3] drm/msm/dp: Avoid a long timeout for AUX transfer if nothing connected Date: Tue, 12 Mar 2024 17:13:16 -0700 Message-ID: <20240312171305.1.I16aff881c9fe82b5e0fc06ca312da017aa7b5b3e@changeid> X-Mailer: git-send-email 2.44.0.278.ge034bb2e1d-goog In-Reply-To: <20240313001345.2623074-1-dianders@chromium.org> References: <20240313001345.2623074-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" As documented in the description of the transfer() function of "struct drm_dp_aux", the transfer() function can be called at any time regardless of the state of the DP port. Specifically if the kernel has the DP AUX character device enabled and userspace accesses "/dev/drm_dp_auxN" directly then the AUX transfer function will be called regardless of whether a DP device is connected. For eDP panels we have a special rule where we wait (with a 5 second timeout) for HPD to go high. This rule was important before all panels drivers were converted to call wait_hpd_asserted() and actually can be removed in a future commit. For external DP devices we never checked for HPD. That means that trying to access the DP AUX character device (AKA `hexdump -C /dev/drm_dp_auxN`) would very, very slowly timeout. Specifically on my system: $ time hexdump -C /dev/drm_dp_aux0 hexdump: /dev/drm_dp_aux0: Connection timed out real 0m8.200s Let's add a check for HPD to avoid the slow timeout. This matches what, for instance, the intel_dp_aux_xfer() function does when it calls intel_tc_port_connected_locked(). That call has a document by it explaining that it's important to avoid the long timeouts. Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Signed-off-by: Douglas Anderson --- drivers/gpu/drm/msm/dp/dp_aux.c | 8 +++++++- drivers/gpu/drm/msm/dp/dp_catalog.c | 10 ++++++++++ drivers/gpu/drm/msm/dp/dp_catalog.h | 1 + 3 files changed, 18 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c index 03f4951c49f4..de0b0eabced9 100644 --- a/drivers/gpu/drm/msm/dp/dp_aux.c +++ b/drivers/gpu/drm/msm/dp/dp_aux.c @@ -307,7 +307,8 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux, * turned on the panel and then tried to do an AUX transfer. The panel * driver has no way of knowing when the panel is ready, so it's up * to us to wait. For DP we never get into this situation so let's - * avoid ever doing the extra long wait for DP. + * avoid ever doing the extra long wait for DP and just query HPD + * directly. */ if (aux->is_edp) { ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog); @@ -315,6 +316,11 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux, DRM_DEBUG_DP("Panel not ready for aux transactions\n"); goto exit; } + } else { + if (!dp_catalog_aux_is_hpd_connected(aux->catalog)) { + ret = -ENXIO; + goto exit; + } } dp_aux_update_offset_and_segment(aux, msg); diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c index 5142aeb705a4..93e2d413a1e7 100644 --- a/drivers/gpu/drm/msm/dp/dp_catalog.c +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c @@ -266,6 +266,16 @@ int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog) 2000, 500000); } +bool dp_catalog_aux_is_hpd_connected(struct dp_catalog *dp_catalog) +{ + struct dp_catalog_private *catalog = container_of(dp_catalog, + struct dp_catalog_private, dp_catalog); + + /* poll for hpd connected status every 2ms and timeout after 500ms */ + return readl(catalog->io->dp_controller.aux.base + REG_DP_DP_HPD_INT_STATUS) & + DP_DP_HPD_STATE_STATUS_CONNECTED; +} + static void dump_regs(void __iomem *base, int len) { int i; diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h index 38786e855b51..1694040c530f 100644 --- a/drivers/gpu/drm/msm/dp/dp_catalog.h +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h @@ -86,6 +86,7 @@ void dp_catalog_aux_reset(struct dp_catalog *dp_catalog); void dp_catalog_aux_enable(struct dp_catalog *dp_catalog, bool enable); void dp_catalog_aux_update_cfg(struct dp_catalog *dp_catalog); int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog); +bool dp_catalog_aux_is_hpd_connected(struct dp_catalog *dp_catalog); u32 dp_catalog_aux_get_irq(struct dp_catalog *dp_catalog); /* DP Controller APIs */ From patchwork Wed Mar 13 00:13:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 13590785 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7E891C54E60 for ; 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Tue, 12 Mar 2024 17:14:01 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2620:15c:9d:2:f8dd:895c:e876:6edb]) by smtp.gmail.com with ESMTPSA id x8-20020a170902a38800b001dd761faec3sm7432924pla.251.2024.03.12.17.13.59 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Mar 2024 17:13:59 -0700 (PDT) From: Douglas Anderson To: Rob Clark , Abhinav Kumar , Dmitry Baryshkov Cc: Douglas Anderson , Daniel Vetter , David Airlie , Kuogee Hsieh , Marijn Suijten , Sankeerth Billakanti , Sean Paul , Vinod Polimera , dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2/3] drm/msm/dp: Account for the timeout in wait_hpd_asserted() callback Date: Tue, 12 Mar 2024 17:13:17 -0700 Message-ID: <20240312171305.2.I7758d18a1773821fa39c034b16a12ef3f18a51ee@changeid> X-Mailer: git-send-email 2.44.0.278.ge034bb2e1d-goog In-Reply-To: <20240313001345.2623074-1-dianders@chromium.org> References: <20240313001345.2623074-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" The DP wait_hpd_asserted() callback is passed a timeout which indicates how long we should wait for HPD. This timeout was being ignored in the MSM DP implementation and instead a hardcoded 500 ms timeout was used. Fix it to use the proper timeout. As part of this we move the hardcoded 500 ms number into the AUX transfer function, which isn't given a timeout. The wait in the AUX transfer function will be removed in a future commit. Fixes: e2969ee30252 ("drm/msm/dp: move of_dp_aux_populate_bus() to eDP probe()") Signed-off-by: Douglas Anderson --- drivers/gpu/drm/msm/dp/dp_aux.c | 5 +++-- drivers/gpu/drm/msm/dp/dp_catalog.c | 7 ++++--- drivers/gpu/drm/msm/dp/dp_catalog.h | 3 ++- 3 files changed, 9 insertions(+), 6 deletions(-) diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c index de0b0eabced9..fc398e8a69a7 100644 --- a/drivers/gpu/drm/msm/dp/dp_aux.c +++ b/drivers/gpu/drm/msm/dp/dp_aux.c @@ -311,7 +311,8 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux, * directly. */ if (aux->is_edp) { - ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog); + ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog, + 500000); if (ret) { DRM_DEBUG_DP("Panel not ready for aux transactions\n"); goto exit; @@ -516,7 +517,7 @@ static int dp_wait_hpd_asserted(struct drm_dp_aux *dp_aux, aux = container_of(dp_aux, struct dp_aux_private, dp_aux); pm_runtime_get_sync(aux->dev); - ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog); + ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog, wait_us); pm_runtime_put_sync(aux->dev); return ret; diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.c b/drivers/gpu/drm/msm/dp/dp_catalog.c index 93e2d413a1e7..b45cf3174aa0 100644 --- a/drivers/gpu/drm/msm/dp/dp_catalog.c +++ b/drivers/gpu/drm/msm/dp/dp_catalog.c @@ -253,17 +253,18 @@ void dp_catalog_aux_update_cfg(struct dp_catalog *dp_catalog) phy_calibrate(phy); } -int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog) +int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog, + unsigned long wait_us) { u32 state; struct dp_catalog_private *catalog = container_of(dp_catalog, struct dp_catalog_private, dp_catalog); - /* poll for hpd connected status every 2ms and timeout after 500ms */ + /* poll for hpd connected status every 2ms and timeout after wait_us */ return readl_poll_timeout(catalog->io->dp_controller.aux.base + REG_DP_DP_HPD_INT_STATUS, state, state & DP_DP_HPD_STATE_STATUS_CONNECTED, - 2000, 500000); + min(wait_us, 2000), wait_us); } bool dp_catalog_aux_is_hpd_connected(struct dp_catalog *dp_catalog) diff --git a/drivers/gpu/drm/msm/dp/dp_catalog.h b/drivers/gpu/drm/msm/dp/dp_catalog.h index 1694040c530f..4248c8de5cf7 100644 --- a/drivers/gpu/drm/msm/dp/dp_catalog.h +++ b/drivers/gpu/drm/msm/dp/dp_catalog.h @@ -85,7 +85,8 @@ int dp_catalog_aux_clear_hw_interrupts(struct dp_catalog *dp_catalog); void dp_catalog_aux_reset(struct dp_catalog *dp_catalog); void dp_catalog_aux_enable(struct dp_catalog *dp_catalog, bool enable); void dp_catalog_aux_update_cfg(struct dp_catalog *dp_catalog); -int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog); +int dp_catalog_aux_wait_for_hpd_connect_state(struct dp_catalog *dp_catalog, + unsigned long wait_us); bool dp_catalog_aux_is_hpd_connected(struct dp_catalog *dp_catalog); u32 dp_catalog_aux_get_irq(struct dp_catalog *dp_catalog); From patchwork Wed Mar 13 00:13:18 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Doug Anderson X-Patchwork-Id: 13590786 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 793B2C54E5D for ; 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Tue, 12 Mar 2024 17:14:03 -0700 (PDT) Received: from dianders.sjc.corp.google.com ([2620:15c:9d:2:f8dd:895c:e876:6edb]) by smtp.gmail.com with ESMTPSA id x8-20020a170902a38800b001dd761faec3sm7432924pla.251.2024.03.12.17.14.01 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Mar 2024 17:14:01 -0700 (PDT) From: Douglas Anderson To: Rob Clark , Abhinav Kumar , Dmitry Baryshkov Cc: Douglas Anderson , Daniel Vetter , David Airlie , Kuogee Hsieh , Marijn Suijten , Sean Paul , dri-devel@lists.freedesktop.org, freedreno@lists.freedesktop.org, linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 3/3] drm/msm/dp: Delete the old 500 ms wait for eDP HPD in aux transfer Date: Tue, 12 Mar 2024 17:13:18 -0700 Message-ID: <20240312171305.3.I535606f6d4f7e3e5588bb75c55996f61980183cd@changeid> X-Mailer: git-send-email 2.44.0.278.ge034bb2e1d-goog In-Reply-To: <20240313001345.2623074-1-dianders@chromium.org> References: <20240313001345.2623074-1-dianders@chromium.org> MIME-Version: 1.0 X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Before the introduction of the wait_hpd_asserted() callback in commit 841d742f094e ("drm/dp: Add wait_hpd_asserted() callback to struct drm_dp_aux") the API between panel drivers and DP AUX bus drivers was that it was up to the AUX bus driver to wait for HPD in the transfer() function. Now wait_hpd_asserted() has been added. The two panel drivers that are DP AUX endpoints use it. See commit 2327b13d6c47 ("drm/panel-edp: Take advantage of wait_hpd_asserted() in struct drm_dp_aux") and commit 3b5765df375c ("drm/panel: atna33xc20: Take advantage of wait_hpd_asserted() in struct drm_dp_aux"). We've implemented wait_hpd_asserted() in the MSM DP driver as of commit e2969ee30252 ("drm/msm/dp: move of_dp_aux_populate_bus() to eDP probe()"). There is no longer any reason for long wait in the AUX transfer() function. Remove it. NOTE: the wait_hpd_asserted() is listed as "optional". That means it's optional for the DP AUX bus to implement. In the case of the MSM DP driver we implement it so we can assume it will be called. ALSO NOTE: the wait wasn't actually _hurting_ anything and wasn't even causing long timeouts, but it's still nice to get rid of unneeded code. Specificaly it's not truly needed because to handle other DP drivers that can't power on as quickly (specifically parade-ps8640) we already avoid DP AUX transfers for eDP panels that aren't powered on. See commit 8df1ddb5bf11 ("drm/dp: Don't attempt AUX transfers when eDP panels are not powered"). Signed-off-by: Douglas Anderson --- drivers/gpu/drm/msm/dp/dp_aux.c | 26 +++++++------------------- 1 file changed, 7 insertions(+), 19 deletions(-) diff --git a/drivers/gpu/drm/msm/dp/dp_aux.c b/drivers/gpu/drm/msm/dp/dp_aux.c index fc398e8a69a7..dd62ad6007a6 100644 --- a/drivers/gpu/drm/msm/dp/dp_aux.c +++ b/drivers/gpu/drm/msm/dp/dp_aux.c @@ -302,26 +302,14 @@ static ssize_t dp_aux_transfer(struct drm_dp_aux *dp_aux, } /* - * For eDP it's important to give a reasonably long wait here for HPD - * to be asserted. This is because the panel driver may have _just_ - * turned on the panel and then tried to do an AUX transfer. The panel - * driver has no way of knowing when the panel is ready, so it's up - * to us to wait. For DP we never get into this situation so let's - * avoid ever doing the extra long wait for DP and just query HPD - * directly. + * If HPD isn't asserted then the transfer won't succeed. Return + * right away. If we don't do this we can end up with long timeouts + * if someone tries to access the DP AUX character device when no + * DP device is connected. */ - if (aux->is_edp) { - ret = dp_catalog_aux_wait_for_hpd_connect_state(aux->catalog, - 500000); - if (ret) { - DRM_DEBUG_DP("Panel not ready for aux transactions\n"); - goto exit; - } - } else { - if (!dp_catalog_aux_is_hpd_connected(aux->catalog)) { - ret = -ENXIO; - goto exit; - } + if (!dp_catalog_aux_is_hpd_connected(aux->catalog)) { + ret = -ENXIO; + goto exit; } dp_aux_update_offset_and_segment(aux, msg);