From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.5]) (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 31E584DE709; Tue, 22 Sep 2026 12:29:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.5 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790080189; cv=none; b=qllAtLmaxWUaTUJPBRVpnoOT6LyAuF9168cE4kZUCkuVUUWPRzjww82ssFB9xzBlxlimVnbWwGXdewE117ZzOjYU+671uGYG+jUgzeKrJ12db28CcKX0d+U+Igfm0dGY1mwIA2uixu1tkOYE4sr2iEBprxxtmJLPBDq9a0+FYSo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790080189; c=relaxed/simple; bh=KU35ZgJCdQmM7U1D/p1QeRnDbQyUHADK+Jj6A02kj9U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=mrnDp7nsM+Jw2W1syFXwOe/CziJulbqnOlhF45hCfoQq5G+IfH7oMAdjKi2ld1xODDGNDBv1AKcSEHPAul8YSsqqLGYrKvghexPNpF9cTENxKO8KaM4q0g7WPya4Ol9A5ej+3oE2/ZTyH24SODHrUcrDof2qKf0zzxRQ8ib6oKI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=dy/2+TNL; arc=none smtp.client-ip=192.198.163.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="dy/2+TNL" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1790080188; x=1821616188; h=date:from:to:cc:subject:message-id:references: mime-version:in-reply-to; bh=KU35ZgJCdQmM7U1D/p1QeRnDbQyUHADK+Jj6A02kj9U=; b=dy/2+TNLOcGHs0s//Tl/v0qT78EeDSKk0I2jL5k/k0cGpu/nG84DPm9y K/o1ZhVlWwaF6fEAyls5emiWPHUc8xYS35VjrX+nHAwP+0jYbQGDT8n6/ gH4Z2fcOaMMajdwrxmzBSZ9FiRUFPDXtBQSix+9mMX8FmmzyhG1Gyxhvn EaMsGjvjB/N7fdx7hC2Ec3JC5/ZtU1HF8CPwr6kCifD4nj3o4zIqWsg/O NrR0Uy8VzPQwhAGCsEAZZ6WQq4YS3Vvp/weBMJl2ruUFns5gZLu5lJWmH 5EHNbkKV3685TofNFfKoEtpWBJY9AMlzB4PsC+X3QTvKutnAwl2vBW4S4 g==; X-CSE-ConnectionGUID: W+1Qc2b6TlqWPdjdfglkaQ== X-CSE-MsgGUID: PwkB5JCNQ2iYt9t231iUBA== X-IronPort-AV: E=McAfee;i="6800,10657,11912"; a="1180596" X-IronPort-AV: E=Sophos;i="6.27,116,1787036400"; d="scan'208";a="1180596" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa115.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Sep 2026 05:29:47 -0700 X-CSE-ConnectionGUID: 78aOL48pQDaU1E51ZgVIhA== X-CSE-MsgGUID: ph9qbkGmTfOIDTZaOo5JrQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,116,1787036400"; d="scan'208";a="277897976" Received: from black.igk.intel.com ([10.91.253.5]) by fmviesa004.fm.intel.com with ESMTP; 22 Sep 2026 05:29:45 -0700 Received: by black.igk.intel.com (Postfix, from userid 1008) id 265BD99; Tue, 22 Sep 2026 14:29:40 +0200 (CEST) Date: Tue, 22 Sep 2026 14:29:40 +0200 From: Heikki Krogerus To: jens.glathe@oldschoolsolutions.biz Cc: Greg Kroah-Hartman , Abel Vesa , Bjorn Andersson , Konrad Dybcio , Sebastian Reichel , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org, stable@vger.kernel.org, "Dr. David Alan Gilbert" , Dmitry Baryshkov Subject: Re: [PATCH v4 3/3] usb: typec: mux: ps883x: disable USB4 on incomplete USB4 platforms Message-ID: References: <20260922-ps883x-disable-usb4-v4-0-0a7b5b70cba3@oldschoolsolutions.biz> <20260922-ps883x-disable-usb4-v4-3-0a7b5b70cba3@oldschoolsolutions.biz> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260922-ps883x-disable-usb4-v4-3-0a7b5b70cba3@oldschoolsolutions.biz> On Tue, Sep 22, 2026 at 02:20:21PM +0200, Jens Glathe via B4 Relay wrote: > From: Jens Glathe > > On Qualcomm X1E80100 / X1P42100 platforms using the Parade PS883x > retimer, hotplugging USB4-capable docks such as the Lenovo 40B0 can > result in working USB but no DisplayPort output. > > When the dock negotiates USB4, the retimer receives TYPEC_MODE_USB4 > and forwards it via typec_mux_set(). The qmp-combo PHY then selects > USB3-only because no classic DP altmode SVID is present in the state, > leaving the DP transmitter and AUX channel disabled. > > Reject USB4 with -EOPNOTSUPP on platforms whose USB4 / DP-tunneling > stack is not ready yet. The Type-C stack then falls back to USB3 + DP > Alt Mode. DP altmode configuration continues to use the existing > ps883x_set() path. > > Use a machine-compatible table rather than a DT property so the quirk > stays inside the kernel and can be removed later without creating ABI. > > Assisted-by: Grok(xAI):4.6 > Tested-by: Dr. David Alan Gilbert > Signed-off-by: Jens Glathe Acked-by: Heikki Krogerus > --- > drivers/usb/typec/mux/ps883x.c | 37 +++++++++++++++++++++++++++++++++++++ > 1 file changed, 37 insertions(+) > > diff --git a/drivers/usb/typec/mux/ps883x.c b/drivers/usb/typec/mux/ps883x.c > index 15aee1d613b1a..2ec57cfe748a9 100644 > --- a/drivers/usb/typec/mux/ps883x.c > +++ b/drivers/usb/typec/mux/ps883x.c > @@ -13,6 +13,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -42,6 +43,22 @@ > #define CONN_STATUS_2_TBT_UNIDIR_LSRX_ACT_LT BIT(4) > #define CONN_STATUS_2_USB4_CONNECTED BIT(7) > > +/* > + * Platforms where the USB4 / DP-tunneling stack is not ready yet. Rejecting > + * USB4 here lets the Type-C stack fall back to USB3 + DP Alt Mode instead of > + * negotiating USB4 and then failing to drive DisplayPort. > + * > + * This is a temporary, kernel-contained quirk (not DT ABI). Drop the entries > + * once the corresponding USB4 support is complete. > + */ > +static const char * const ps883x_disable_usb4_compats[] = { > + "qcom,x1e80100", > + "qcom,x1p42100", > + "qcom,hamoa", > + "qcom,purwa", > + NULL, > +}; > + > struct ps883x_retimer { > struct i2c_client *client; > struct gpio_desc *reset_gpio; > @@ -63,8 +80,21 @@ struct ps883x_retimer { > > enum typec_orientation orientation; > bool in_reset; > + bool disable_usb4; > }; > > +static bool ps883x_should_disable_usb4(void) > +{ > + const char * const *compat; > + > + for (compat = ps883x_disable_usb4_compats; *compat; compat++) { > + if (of_machine_is_compatible(*compat)) > + return true; > + } > + > + return false; > +} > + > static int ps883x_enable_vregs(struct ps883x_retimer *retimer) > { > struct device *dev = &retimer->client->dev; > @@ -260,6 +290,9 @@ static int ps883x_set(struct ps883x_retimer *retimer, struct typec_retimer_state > cfg0 |= CONN_STATUS_0_USB_3_1_CONNECTED; > break; > case TYPEC_MODE_USB4: > + if (retimer->disable_usb4) > + return -EOPNOTSUPP; > + > eudo_data = state->data; > > cfg2 |= CONN_STATUS_2_USB4_CONNECTED; > @@ -389,6 +422,10 @@ static int ps883x_retimer_probe(struct i2c_client *client) > > retimer->client = client; > > + retimer->disable_usb4 = ps883x_should_disable_usb4(); > + if (retimer->disable_usb4) > + dev_info(dev, "USB4 disabled until platform USB4 support is complete\n"); > + > mutex_init(&retimer->lock); > > retimer->regmap = devm_regmap_init_i2c(client, &ps883x_retimer_regmap); > > -- > 2.53.0 > -- heikki