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 07C88CDB470 for ; Tue, 23 Jun 2026 20:51:50 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 6DD3E10ECB2; Tue, 23 Jun 2026 20:51:49 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="WVVS3Osz"; dkim-atps=neutral Received: from sea.source.kernel.org (sea.source.kernel.org [172.234.252.31]) by gabe.freedesktop.org (Postfix) with ESMTPS id 8CA8810ECB2 for ; Tue, 23 Jun 2026 20:51:48 +0000 (UTC) Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 5FF7F41A49; Tue, 23 Jun 2026 20:51:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2DC61F000E9; Tue, 23 Jun 2026 20:51:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1782247908; bh=2r3F2fqRrB3QUJWG7R7MxVMUzAVNliS74R6UCPnQhuM=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=WVVS3OszbkEGzSzX0Q+ipz3UAFehN1ZbtrulmRF7tdCW7LoWYUuQ8J7fML4dbGYFJ wcleOEgqGH48tTnEUC96bz8d/EMwJ8vb04x/cj/MEYLb1Hje8PP/rGYRCiXv/kZDWI XIIDtUNzfIfCT3bn0ORZCosmchoe518XITgkFeLUW+duMwBgh7qpjhVISwSpFN6NEc fZJ9OLSzLSksUv9qGSFh+gaEc5BqZDQF+OP7HKt5yzokrlrTFdR5/sKNBxh5h0aqyU UR2ug4TLWlrADzZb3a2cwi2NuNT4K94dgYZBviilTsDZV3MDj8X7OsIOgn+SR7Hviu qZ5Ro9l+lDHWw== From: sashiko-bot@kernel.org Subject: Re: [PATCH RFC v3 09/10] dt-bindings: display: rockchip: dw-dp: fix sound DAI cells To: "Sebastian Reichel" Cc: conor+dt@kernel.org, devicetree@vger.kernel.org, robh@kernel.org, dri-devel@lists.freedesktop.org In-Reply-To: <20260612-synopsys-dw-dp-improvements-v3-9-dc61e6352508@collabora.com> References: <20260612-synopsys-dw-dp-improvements-v3-9-dc61e6352508@collabora.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 23 Jun 2026 20:51:47 +0000 Message-Id: <20260623205147.F2DC61F000E9@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 4 potential issue(= s) to consider: - [Critical] Unconditionally changing `#sound-dai-cells` from `const: 0` to= `const: 1` breaks backward compatibility with existing device tree binarie= s and causes `make dtbs_check` failures. - [High] dw_dp_runtime_resume() fails to check the return value of clk_prep= are_enable() for apb_clk and aux_clk, leading to unclocked hardware accesse= s. - [High] The driver ignores the return value of pm_runtime_get_sync() and i= ts scoped guard wrappers, leading to potential unclocked register accesses. - [Medium] The `#sound-dai-cells =3D <1>` design is mathematically insuffic= ient to support the RK3576's 6 DAI interfaces, ensuring future ABI breakage= when MST is fully implemented. -- commit dcfc80f29db8ade71eb0e49550ea25781716e785 Author: Sebastian Reichel dt-bindings: display: rockchip: dw-dp: fix sound DAI cells This commit updates the #sound-dai-cells property to support the two possible DAI interfaces (I2S and S/PDIF) on RK3588 and RK3576 DesignWare DisplayPort controllers. It changes the const value to 1 and discusses options for future Multi Stream Transport (MST) support. > diff --git a/Documentation/devicetree/bindings/display/rockchip/rockchip,= dw-dp.yaml b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw= -dp.yaml > index 2b0d9e23e9432..1303d0e2145a9 100644 > --- a/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-dp.y= aml > +++ b/Documentation/devicetree/bindings/display/rockchip/rockchip,dw-dp.y= aml > @@ -83,7 +83,8 @@ properties: > maxItems: 1 > =20 > "#sound-dai-cells": > - const: 0 > + const: 1 > + description: 0 for I2S, 1 for SPDIF [Severity: Critical] Does unconditionally changing #sound-dai-cells from const: 0 to const: 1 break backward compatibility with existing device tree binaries? Existing device trees supplying 0 cells will now fail validation during make dtbs_check, and older DTBs will no longer conform to the schema. [Severity: Medium] Is setting #sound-dai-cells =3D <1> mathematically sufficient to support the RK3576 hardware? The commit message mentions the RK3576 features MST with 6 DAIs, so a single cell constraint only supports 2 states (I2S and S/PDIF). Will this necessit= ate another breaking change when MST is implemented? > =20 > required: > - compatible [ ... ] > diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/br= idge/synopsys/dw-dp.c > index 36ee6e027af52..7f4f36c614844 100644 > --- a/drivers/gpu/drm/bridge/synopsys/dw-dp.c > +++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c [ ... ] > @@ -1651,6 +1657,8 @@ static void dw_dp_bridge_atomic_enable(struct drm_b= ridge *bridge, > struct drm_connector_state *conn_state; > int ret; > =20 > + pm_runtime_get_sync(dp->dev); > + [Severity: High] Does this code discard the return value of pm_runtime_get_sync()? If the PM core fails to resume the device, the code proceeds with the enable sequence, which could risk unclocked register accesses later on. > connector =3D drm_atomic_get_new_connector_for_encoder(state, bridge->e= ncoder); > if (!connector) { > dev_err(dp->dev, "failed to get connector\n"); [ ... ] > @@ -1725,6 +1734,8 @@ static enum drm_connector_status dw_dp_bridge_detec= t(struct drm_bridge *bridge, > { > struct dw_dp *dp =3D bridge_to_dp(bridge); > =20 > + ACQUIRE(pm_runtime_active_auto, pm)(dp->dev); > + > if (!dw_dp_hpd_detect(dp)) [Severity: High] Does using this unconditional PM scope guard discard the return value? If the device failed to resume, the code will proceed to access hardware registers in dw_dp_hpd_detect(), which could trigger a bus fault. > return connector_status_disconnected; > =20 > if (!dw_dp_hpd_detect_link(dp, connector)) [ ... ] > @@ -2099,6 +2160,26 @@ void dw_dp_unbind(struct dw_dp *dp) > } > EXPORT_SYMBOL_GPL(dw_dp_unbind); > =20 > +int dw_dp_runtime_suspend(struct dw_dp *dp) > +{ > + clk_disable_unprepare(dp->aux_clk); > + clk_disable_unprepare(dp->apb_clk); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(dw_dp_runtime_suspend); > + > +int dw_dp_runtime_resume(struct dw_dp *dp) > +{ > + clk_prepare_enable(dp->apb_clk); > + clk_prepare_enable(dp->aux_clk); > + [Severity: High] Are we ignoring the return values of clk_prepare_enable() here? If the clocks fail to enable, unconditionally calling dw_dp_init_hw() will access hardware registers while unclocked, which could lead to a bus hang. > + dw_dp_init_hw(dp); > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(dw_dp_runtime_resume); [ ... ] > diff --git a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c b/drivers/gpu/drm/= rockchip/dw_dp-rockchip.c > index 0de822360c8db..1f53228e56d9f 100644 > --- a/drivers/gpu/drm/rockchip/dw_dp-rockchip.c > +++ b/drivers/gpu/drm/rockchip/dw_dp-rockchip.c [ ... ] > +static void dw_dp_rockchip_hpd_sw_sel(void *data, bool force_hpd_from_sw) > +{ > + struct rockchip_dw_dp *dp =3D data; > + u32 hpd_reg =3D dp->pdata->hpd_reg[dp->id]; > + > + dp->hpd_sel =3D force_hpd_from_sw; > + > + ACQUIRE(pm_runtime_active_auto, pm)(dp->dev); > + > + regmap_write(dp->vo_grf, hpd_reg, > + FIELD_PREP_WM16(ROCKCHIP_VO_GRF_DP_SINK_HPD_SEL, dp->hpd_sel)); [Severity: High] Does this ignore the possibility that the power domain failed to resume? If the unconditional PM guard fails, writing to the vo_grf syscon will trigger a bus fault. > +} --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260612-synopsys-d= w-dp-improvements-v3-0-dc61e6352508@collabora.com?part=3D9