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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 A9464CD8C8C for ; Sun, 7 Jun 2026 21:48:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Reply-To:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: References:In-Reply-To:Cc:To:Subject:From:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=Ub4KzYB7NIXSeXWaSyrt3KAIgMwElyEjUjXh+nsK4FM=; b=FLi0EjpgaEiAsN Ld8BKMDi3o875ubZKYrue4TrxqAzuB5JFm8RNtIfa5g6YBoZpsoDbGp3XVbS36l8CzczKqmA9tch3 uqvno6SLMBMHmAia7IgwkYsYPDsHjCbO7ZwWUaVnMGmGEi35Z9cH0bltsKtGpfz20oPWeph1/4Y+B 2EILpcnpdLkIcWL7eDDLaWj9YCym+zZMhr48BWcsayV2jramcr81YCk/i14N9D/yAAfC0VST5jHH1 9yjTvQPh2HWscyDgXl4A0syQkOMTNOCZPXzRJGYEheGfz64git1nPZ3Bq5O3QYDXPpkxFNZEZtkri OCx13ac5BWDinDx1qd8g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wWLM8-00000002X2n-1B0T; Sun, 07 Jun 2026 21:48:32 +0000 Received: from tor.source.kernel.org ([172.105.4.254]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wWLM6-00000002X2Z-3Jzu for linux-amlogic@lists.infradead.org; Sun, 07 Jun 2026 21:48:30 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 3FEEB60018; Sun, 7 Jun 2026 21:48:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B05091F00893; Sun, 7 Jun 2026 21:48:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780868910; bh=U8/nAEIUsIEuWNhzHG7THuc153jQDkJAzRdpq4tLzZM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=kCkTKb1D/8B8+RSIzStZbrpXcdbecpV33zyZzGdOB90Bdp7QyfyKCLE8X63+liL42 cxYuLgXeVh2VydzTqidijq9JOD76nvMULXEu6u3FGSaMIYV2uzeu55c+3FZ8dbNme4 4G+XElSTMlTqh1aro4r4WmnhxccJ8rTSXbZGEOGkoygNRj8HPfKPF/fnR2y95nFaBc J05GfWPDVX3UjKmWky6GiXyswbC89esphgTKrIiMqv+bvnu+s7aZymt5xbQxMwVOHz srBVtiLCO4R6QjLcht9vvhfXT+O/h54JWgYqzK7CkCnG8PLsOxKgN+I3cc42LJVyXS IFiwDAT7TS36Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 6/8] drm/msm: dp: handle the IRQ_HPD events reported by USB-C To: "Dmitry Baryshkov" Cc: linux-amlogic@lists.infradead.org, dri-devel@lists.freedesktop.org, neil.armstrong@linaro.org In-Reply-To: <20260608-hpd-irq-events-v4-6-30b62b335487@oss.qualcomm.com> References: <20260608-hpd-irq-events-v4-6-30b62b335487@oss.qualcomm.com> Date: Sun, 07 Jun 2026 21:48:29 +0000 Message-Id: <20260607214829.B05091F00893@smtp.kernel.org> X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: sashiko-reviews@lists.linux.dev MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org VGhhbmsgeW91IGZvciB5b3VyIGNvbnRyaWJ1dGlvbiEgU2FzaGlrbyBBSSByZXZpZXcgZm91bmQg MiBwb3RlbnRpYWwgaXNzdWUocykgdG8gY29uc2lkZXI6CgpOZXcgaXNzdWVzOgotIFtIaWdoXSBJ bml0aWFsIGNvbm5lY3Rpb24gYW5kIHJlcGx1ZyBldmVudHMgYXJlIGluY29ycmVjdGx5IGJ5cGFz c2VkIGlmIGFjY29tcGFuaWVkIGJ5IGFuIElSUV9IUEQgc3RhdHVzLCBsZWF2aW5nIHRoZSBkaXNw bGF5IGRpc2Nvbm5lY3RlZC4KClByZS1leGlzdGluZyBpc3N1ZXM6Ci0gW0hpZ2hdIGBtc21fZHBf aXJxX2hwZF9oYW5kbGVgIG1vZGlmaWVzIHNoYXJlZCBzdGF0ZSB3aXRob3V0IGFjcXVpcmluZyBg ZHAtPnBsdWdnZWRfbG9ja2AsIGxlYWRpbmcgdG8gdW5wcm90ZWN0ZWQgY29uY3VycmVudCBtb2Rp ZmljYXRpb24gb2YgRFBDRCBhbmQgbGluayBzdGF0ZS4KLS0KCmNvbW1pdCA0OGE3ODM1OGFlOTgw MjBmZjM5OTNhYWIzMjUwZGQ4YzMyY2M2ODM1CkF1dGhvcjogRG1pdHJ5IEJhcnlzaGtvdiA8ZG1p dHJ5LmJhcnlzaGtvdkBvc3MucXVhbGNvbW0uY29tPgoKZHJtL21zbTogZHA6IGhhbmRsZSB0aGUg SVJRX0hQRCBldmVudHMgcmVwb3J0ZWQgYnkgVVNCLUMKClRoaXMgcGF0Y2ggYWRkcyBzdXBwb3J0 IGZvciB0cmFja2luZyBhbmQgaGFuZGxpbmcgSVJRX0hQRCBldmVudHMKZGVsaXZlcmVkIG92ZXIg b3V0LW9mLWJhbmQgZXZlbnRzIChzdWNoIGFzIFVTQi1DIEFsdE1vZGUgaGFuZGxlcnMpCmluIHRo ZSBNU00gRGlzcGxheVBvcnQgZHJpdmVyLgoKPiBkaWZmIC0tZ2l0IGEvZHJpdmVycy9ncHUvZHJt L21zbS9kcC9kcF9kaXNwbGF5LmMgYi9kcml2ZXJzL2dwdS9kcm0vbXNtL2RwL2RwX2Rpc3BsYXku Ywo+IGluZGV4IGMwZjZhOGZmOWI5OWQuLjc0M2Q4ZmE0MGRjNjggMTAwNjQ0Cj4gLS0tIGEvZHJp dmVycy9ncHUvZHJtL21zbS9kcC9kcF9kaXNwbGF5LmMKPiArKysgYi9kcml2ZXJzL2dwdS9kcm0v bXNtL2RwL2RwX2Rpc3BsYXkuYwo+IEBAIC0xNTMzLDExICsxNTMzLDEyIEBAIHZvaWQgbXNtX2Rw X2JyaWRnZV9ocGRfbm90aWZ5KHN0cnVjdCBkcm1fYnJpZGdlICpicmlkZ2UsCj4gIAkJICAgbXNt X2RwX2Rpc3BsYXktPmNvbm5lY3Rvcl90eXBlLCBocGRfbGlua19zdGF0dXMsIHN0YXR1cyk7Cj4g IAo+ICAJaWYgKHN0YXR1cyA9PSBjb25uZWN0b3Jfc3RhdHVzX2Nvbm5lY3RlZCkgewo+IC0JCWlm IChocGRfbGlua19zdGF0dXMgPT0gSVNSX0hQRF9SRVBMVUdfQ09VTlQpIHsKPiArCQlpZiAoaHBk X2xpbmtfc3RhdHVzID09IElTUl9JUlFfSFBEX1BVTFNFX0NPVU5UIHx8Cj4gKwkJICAgIGV4dHJh X3N0YXR1cyA9PSBEUk1fQ09OTkVDVE9SX0RQX0lSUV9IUEQpIHsKPiArCQkJbXNtX2RwX2lycV9o cGRfaGFuZGxlKGRwKTsKCltTZXZlcml0eTogSGlnaF0KVGhpcyBpcyBhIHByZS1leGlzdGluZyBp c3N1ZSwgYnV0IGRvZXMgbXNtX2RwX2lycV9ocGRfaGFuZGxlKCkgbmVlZCB0bwphY3F1aXJlIHRo ZSBkcC0+cGx1Z2dlZF9sb2NrPwoKU2luY2UgbXNtX2RwX2lycV9ocGRfaGFuZGxlKCkgY2FuIGNh bGwgbXNtX2RwX2Rpc3BsYXlfcHJvY2Vzc19ocGRfaGlnaCgpLAp3aGljaCByZWFkcyBmcm9tIERQ Q0QgYW5kIG1vZGlmaWVzIHNoYXJlZCBkcml2ZXIgc3RhdGUgKGxpa2UKZHAtPmxpbmstPmx0dHBy X2NvdW50LCBkcC0+cGFuZWwtPmRwY2QsIGFuZCBkcC0+YXVkaW9fc3VwcG9ydGVkKSwgaXQgc2Vl bXMKbGlrZSBpdCBjb3VsZCByYWNlLiBPdGhlciBIUEQgaGFuZGxlcnMgbGlrZSBtc21fZHBfaHBk X3BsdWdfaGFuZGxlKCkgdXNlCmd1YXJkKG11dGV4KSgmZHAtPnBsdWdnZWRfbG9jaykgdG8gc2Fm ZWx5IHN5bmNocm9uaXplIGFjY2Vzcy4KCldpdGggb3V0LW9mLWJhbmQgZXZlbnRzIHByb2Nlc3Nl ZCB2aWEgd29ya3F1ZXVlcywgY2FuIHRoaXMgZnVuY3Rpb24KcnVuIGNvbmN1cnJlbnRseSB3aXRo IG90aGVyIEhQRCBoYW5kbGVycyBvciBtc21fZHBfYnJpZGdlX2RldGVjdCgpIGFuZApjb3JydXB0 IHRoZSBpbnRlcm5hbCByZXByZXNlbnRhdGlvbiBvZiB0aGUgaGFyZHdhcmUgY29uZmlndXJhdGlv bj8KCltTZXZlcml0eTogSGlnaF0KSWYgYW4gb3V0LW9mLWJhbmQgaGFuZGxlciByZXBvcnRzIGFu IGluaXRpYWwgY29ubmVjdGlvbiB3aXRoIGJvdGggaHBkX3N0YXRlPTEKYW5kIGhwZF9pcnE9MSBz aW11bHRhbmVvdXNseSwgZG9lcyB0aGlzIG5ldyBvcmRlcmluZyBieXBhc3MgdGhlIHJlcXVpcmVk IHBsdWcKc2VxdWVuY2U/CgpCeSBwbGFjaW5nIHRoZSBJUlFfSFBEIGNoZWNrIGF0IHRoZSB0b3Ag b2YgdGhlIGlmL2Vsc2UgY2hhaW4sIGlmCmV4dHJhX3N0YXR1cyA9PSBEUk1fQ09OTkVDVE9SX0RQ X0lSUV9IUEQsIHRoZSBjb2RlIHdpbGwgZXhlY3V0ZQptc21fZHBfaXJxX2hwZF9oYW5kbGUoKSBh bmQgc2tpcCBtc21fZHBfaHBkX3BsdWdfaGFuZGxlKCkuCgpJZiBtc21fZHBfaHBkX3BsdWdfaGFu ZGxlKCkgaXMgc2tpcHBlZCwgZHAtPnBsdWdnZWQgcmVtYWlucyBmYWxzZSwgUEhZCmluaXRpYWxp emF0aW9uIChtc21fZHBfZGlzcGxheV9ob3N0X3BoeV9pbml0KSBuZXZlciBvY2N1cnMsIGFuZApt c21fZHBfYXV4X2VuYWJsZV94ZmVycygpIGlzIG5ldmVyIGNhbGxlZC4gV29uJ3QgdGhlIHN1YnNl cXVlbnQgQVVYIHJlYWRzCndpdGhpbiBtc21fZHBfaXJxX2hwZF9oYW5kbGUoKSBmYWlsIHdpdGgg LUVOWElPLCBhYm9ydGluZyB0aGUgaW5pdGlhbGl6YXRpb24KYW5kIGxlYXZpbmcgdGhlIGRpc3Bs YXkgZGlzY29ubmVjdGVkPwoKPiArCQl9IGVsc2UgaWYgKGhwZF9saW5rX3N0YXR1cyA9PSBJU1Jf SFBEX1JFUExVR19DT1VOVCkgewo+ICAJCQltc21fZHBfaHBkX3VucGx1Z19oYW5kbGUoZHApOwo+ ICAJCQltc21fZHBfaHBkX3BsdWdfaGFuZGxlKGRwKTsKPiAtCQl9IGVsc2UgaWYgKGhwZF9saW5r X3N0YXR1cyA9PSBJU1JfSVJRX0hQRF9QVUxTRV9DT1VOVCkgewo+IC0JCQltc21fZHBfaXJxX2hw ZF9oYW5kbGUoZHApOwo+ICAJCX0gZWxzZSB7Cj4gIAkJCW1zbV9kcF9ocGRfcGx1Z19oYW5kbGUo ZHApOwo+ICAJCX0KCi0tIApTYXNoaWtvIEFJIHJldmlldyDCtyBodHRwczovL3Nhc2hpa28uZGV2 LyMvcGF0Y2hzZXQvMjAyNjA2MDgtaHBkLWlycS1ldmVudHMtdjQtMC0zMGI2MmIzMzU0ODdAb3Nz LnF1YWxjb21tLmNvbT9wYXJ0PTYKCl9fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fCmxpbnV4LWFtbG9naWMgbWFpbGluZyBsaXN0CmxpbnV4LWFtbG9naWNAbGlz dHMuaW5mcmFkZWFkLm9yZwpodHRwOi8vbGlzdHMuaW5mcmFkZWFkLm9yZy9tYWlsbWFuL2xpc3Rp bmZvL2xpbnV4LWFtbG9naWMK 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 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 04781CD8C90 for ; Sun, 7 Jun 2026 21:48:33 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5F99F10E67A; Sun, 7 Jun 2026 21:48:32 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="kCkTKb1D"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id D774210E67A for ; Sun, 7 Jun 2026 21:48:30 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id 3FEEB60018; Sun, 7 Jun 2026 21:48:30 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B05091F00893; Sun, 7 Jun 2026 21:48:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1780868910; bh=U8/nAEIUsIEuWNhzHG7THuc153jQDkJAzRdpq4tLzZM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=kCkTKb1D/8B8+RSIzStZbrpXcdbecpV33zyZzGdOB90Bdp7QyfyKCLE8X63+liL42 cxYuLgXeVh2VydzTqidijq9JOD76nvMULXEu6u3FGSaMIYV2uzeu55c+3FZ8dbNme4 4G+XElSTMlTqh1aro4r4WmnhxccJ8rTSXbZGEOGkoygNRj8HPfKPF/fnR2y95nFaBc J05GfWPDVX3UjKmWky6GiXyswbC89esphgTKrIiMqv+bvnu+s7aZymt5xbQxMwVOHz srBVtiLCO4R6QjLcht9vvhfXT+O/h54JWgYqzK7CkCnG8PLsOxKgN+I3cc42LJVyXS IFiwDAT7TS36Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v4 6/8] drm/msm: dp: handle the IRQ_HPD events reported by USB-C To: "Dmitry Baryshkov" Cc: linux-amlogic@lists.infradead.org, dri-devel@lists.freedesktop.org, neil.armstrong@linaro.org In-Reply-To: <20260608-hpd-irq-events-v4-6-30b62b335487@oss.qualcomm.com> References: <20260608-hpd-irq-events-v4-6-30b62b335487@oss.qualcomm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 07 Jun 2026 21:48:29 +0000 Message-Id: <20260607214829.B05091F00893@smtp.kernel.org> 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: , Reply-To: sashiko-reviews@lists.linux.dev Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" Thank you for your contribution! Sashiko AI review found 2 potential issue(= s) to consider: New issues: - [High] Initial connection and replug events are incorrectly bypassed if a= ccompanied by an IRQ_HPD status, leaving the display disconnected. Pre-existing issues: - [High] `msm_dp_irq_hpd_handle` modifies shared state without acquiring `d= p->plugged_lock`, leading to unprotected concurrent modification of DPCD an= d link state. -- commit 48a78358ae98020ff3993aab3250dd8c32cc6835 Author: Dmitry Baryshkov drm/msm: dp: handle the IRQ_HPD events reported by USB-C This patch adds support for tracking and handling IRQ_HPD events delivered over out-of-band events (such as USB-C AltMode handlers) in the MSM DisplayPort driver. > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp= /dp_display.c > index c0f6a8ff9b99d..743d8fa40dc68 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -1533,11 +1533,12 @@ void msm_dp_bridge_hpd_notify(struct drm_bridge *= bridge, > msm_dp_display->connector_type, hpd_link_status, status); > =20 > if (status =3D=3D connector_status_connected) { > - if (hpd_link_status =3D=3D ISR_HPD_REPLUG_COUNT) { > + if (hpd_link_status =3D=3D ISR_IRQ_HPD_PULSE_COUNT || > + extra_status =3D=3D DRM_CONNECTOR_DP_IRQ_HPD) { > + msm_dp_irq_hpd_handle(dp); [Severity: High] This is a pre-existing issue, but does msm_dp_irq_hpd_handle() need to acquire the dp->plugged_lock? Since msm_dp_irq_hpd_handle() can call msm_dp_display_process_hpd_high(), which reads from DPCD and modifies shared driver state (like dp->link->lttpr_count, dp->panel->dpcd, and dp->audio_supported), it seems like it could race. Other HPD handlers like msm_dp_hpd_plug_handle() use guard(mutex)(&dp->plugged_lock) to safely synchronize access. With out-of-band events processed via workqueues, can this function run concurrently with other HPD handlers or msm_dp_bridge_detect() and corrupt the internal representation of the hardware configuration? [Severity: High] If an out-of-band handler reports an initial connection with both hpd_state= =3D1 and hpd_irq=3D1 simultaneously, does this new ordering bypass the required = plug sequence? By placing the IRQ_HPD check at the top of the if/else chain, if extra_status =3D=3D DRM_CONNECTOR_DP_IRQ_HPD, the code will execute msm_dp_irq_hpd_handle() and skip msm_dp_hpd_plug_handle(). If msm_dp_hpd_plug_handle() is skipped, dp->plugged remains false, PHY initialization (msm_dp_display_host_phy_init) never occurs, and msm_dp_aux_enable_xfers() is never called. Won't the subsequent AUX reads within msm_dp_irq_hpd_handle() fail with -ENXIO, aborting the initialization and leaving the display disconnected? > + } else if (hpd_link_status =3D=3D ISR_HPD_REPLUG_COUNT) { > msm_dp_hpd_unplug_handle(dp); > msm_dp_hpd_plug_handle(dp); > - } else if (hpd_link_status =3D=3D ISR_IRQ_HPD_PULSE_COUNT) { > - msm_dp_irq_hpd_handle(dp); > } else { > msm_dp_hpd_plug_handle(dp); > } --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260608-hpd-irq-ev= ents-v4-0-30b62b335487@oss.qualcomm.com?part=3D6