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 D84CAC7EE32 for ; Thu, 26 Jun 2025 10:46:44 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 9E0D410E031; Thu, 26 Jun 2025 10:46:44 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=intel.com header.i=@intel.com header.b="eATw926p"; dkim-atps=neutral Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.13]) by gabe.freedesktop.org (Postfix) with ESMTPS id B7A3D10E031; Thu, 26 Jun 2025 10:46:43 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1750934804; x=1782470804; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=h+bNHNaQuxPjix43ySHDI9RgDW1++St/0DJGlbI7VL0=; b=eATw926pY5/tMBgaO7avt99kFkmb8Uhw9HkmhQCe5GcRsZtshrIQPQKK Ym9wrRJcRjB4gEfXkKi9yP9ITkqEPDCPEJrbbRUGsB7Nah1rrtpSnxtol p8CVniCGzCbY5JZ/NqpI2ooepVeO8PCXb62x0E4iu8mZN++A4TMkFfSrt sbY2xeS1FtAxFSqIaAXNa57xXeSicyQiEZ+dsJxF5DuPyz+TBxnAoNHVH +TkYTaIMMbmsBTmC/83dhG1s8K9fdJiuPlVkIotmiMZ98uJUjug4uVTjP 0ifZb8ppB7/r7CqSTTfXltldYiRnGFHqa+llsS5tmAwfn/vbBSPZ7O/NV w==; X-CSE-ConnectionGUID: +yR3Ci2UTjWzL9ClnIx0/Q== X-CSE-MsgGUID: Tg+FdFcVRLiATvzcLszGgQ== X-IronPort-AV: E=McAfee;i="6800,10657,11475"; a="64287331" X-IronPort-AV: E=Sophos;i="6.16,267,1744095600"; d="scan'208";a="64287331" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jun 2025 03:46:32 -0700 X-CSE-ConnectionGUID: zb6OATTFT+2muF5DXNwQng== X-CSE-MsgGUID: o6vOERFRSSmYYQjHSOg8eg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.16,267,1744095600"; d="scan'208";a="152245902" Received: from dhhellew-desk2.ger.corp.intel.com (HELO localhost) ([10.245.246.120]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jun 2025 03:46:30 -0700 From: Jani Nikula To: imre.deak@intel.com Cc: intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Imre Deak Subject: Re: [PATCH 11/20] drm/i915/dp: Reprobe connector if getting/acking device IRQs fails In-Reply-To: Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20250626082053.219514-1-imre.deak@intel.com> <20250626082053.219514-12-imre.deak@intel.com> <625ce1c9c46ba93027fecadae4803fc86450ad50@intel.com> <9ef664aa1e833ee6c3f97533da4a0d828a03f9f2@intel.com> Date: Thu, 26 Jun 2025 13:46:27 +0300 Message-ID: <9cef5bf7a30fca73313e9b178bf65f1ac2842141@intel.com> MIME-Version: 1.0 Content-Type: text/plain X-BeenThere: intel-xe@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel Xe graphics driver List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-xe-bounces@lists.freedesktop.org Sender: "Intel-xe" On Thu, 26 Jun 2025, Imre Deak wrote: > On Thu, Jun 26, 2025 at 01:23:12PM +0300, Jani Nikula wrote: >> On Thu, 26 Jun 2025, Imre Deak wrote: >> > On Thu, Jun 26, 2025 at 12:12:11PM +0300, Jani Nikula wrote: >> >> On Thu, 26 Jun 2025, Imre Deak wrote: >> >> > From: Imre Deak >> >> > >> >> > An AUX access failure during HPD IRQ handling should be handled by >> >> > falling back to a full connector detection, ensure that if the failure >> >> > happens while reading/acking a device service IRQ. >> >> > >> >> > Signed-off-by: Imre Deak >> >> > --- >> >> > drivers/gpu/drm/i915/display/intel_dp.c | 21 +++++++++++++++------ >> >> > 1 file changed, 15 insertions(+), 6 deletions(-) >> >> > >> >> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c >> >> > index 7793a72983abd..7eb208d2c321b 100644 >> >> > --- a/drivers/gpu/drm/i915/display/intel_dp.c >> >> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c >> >> > @@ -5393,16 +5393,20 @@ void intel_dp_check_link_state(struct intel_dp *intel_dp) >> >> > intel_encoder_link_check_queue_work(encoder, 0); >> >> > } >> >> > >> >> > -static void intel_dp_check_device_service_irq(struct intel_dp *intel_dp) >> >> > +static bool intel_dp_check_device_service_irq(struct intel_dp *intel_dp) >> >> >> >> I don't think "check" is very intuitive in function names. Check >> >> something, but then what? Is it like an assert or does it do something >> >> active or what? >> >> >> >> What does a boolean return from a check function mean? >> >> >> >> It's not obvious to the reader at all. >> > >> > I agree, but in this patch I didn't want to change the function name. >> >> Arguably adding a return value changes the meaning already... >> >> > >> >> >> >> > { >> >> > struct intel_display *display = to_intel_display(intel_dp); >> >> > u8 val; >> >> > >> >> > if (drm_dp_dpcd_readb(&intel_dp->aux, >> >> > - DP_DEVICE_SERVICE_IRQ_VECTOR, &val) != 1 || !val) >> >> > - return; >> >> > + DP_DEVICE_SERVICE_IRQ_VECTOR, &val) != 1) >> >> > + return true; >> >> >> >> Looks like true means the check failed... while usually true for boolean >> >> functions means success. >> > >> > The function returns true as before if a full connector detection is needed. >> >> But it didn't return anything before! And that meaning is not conveyed >> to the reader in *any* reasonable way! > > This function is the counterpart of intel_dp_check_link_service_irq() > both functions having the same purpose, reading and handling HPD IRQs. > The latter one's return value is true if a reprobe is needed and this > patch doesn't change that, it keeps the two functions behave the same > way. > >> The absolute minimum is to add a comment (mind you, kernel-doc is >> overkill) stating what the return value means. > > The function name will change in a follow-up patch and I think that > doesn't require a comment on the return value. > >> >> >> >> > >> >> > - drm_dp_dpcd_writeb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR, val); >> >> > + if (!val) >> >> > + return false; >> >> > + >> >> > + if (drm_dp_dpcd_writeb(&intel_dp->aux, DP_DEVICE_SERVICE_IRQ_VECTOR, val) != 1) >> >> > + return true; >> >> > >> >> > if (val & DP_AUTOMATED_TEST_REQUEST) >> >> > intel_dp_test_request(intel_dp); >> >> >> >> Whoa, it's not a *check* function at all?! It actually *handles* the >> >> service irqs. >> >> >> >> Can we rephrase the function name? >> > >> > I want to keep the function name in this patch. In the following patches >> > I will separate this part and rename it to >> > intel_dp_get_and_ack_device_service_irq(). >> >> Right, saw that now. But even for that function name the meaning of the >> return value is ambiguous. > > All the get/ack IRQ functions in intel_dp.c return true for success. Argh. You just said it doesn't mean success/failure, it means if full connector detection is needed?! BR, Jani > >> >> BR, >> Jani. >> >> > >> > >> >> int intel_dp_handle_device_service_irq() and int returns maybe? >> >> BR, >> >> Jani. >> >> >> >> > @@ -5412,6 +5416,8 @@ static void intel_dp_check_device_service_irq(struct intel_dp *intel_dp) >> >> > >> >> > if (val & DP_SINK_SPECIFIC_IRQ) >> >> > drm_dbg_kms(display->drm, "Sink specific irq unhandled\n"); >> >> > + >> >> > + return false; >> >> > } >> >> > >> >> > static bool intel_dp_check_link_service_irq(struct intel_dp *intel_dp) >> >> > @@ -5476,8 +5482,11 @@ intel_dp_short_pulse(struct intel_dp *intel_dp) >> >> > /* No need to proceed if we are going to do full detect */ >> >> > return false; >> >> > >> >> > - intel_dp_check_device_service_irq(intel_dp); >> >> > - reprobe_needed = intel_dp_check_link_service_irq(intel_dp); >> >> > + if (intel_dp_check_device_service_irq(intel_dp)) >> >> > + reprobe_needed = true; >> >> > + >> >> > + if (intel_dp_check_link_service_irq(intel_dp)) >> >> > + reprobe_needed = true; >> >> > >> >> > /* Handle CEC interrupts, if any */ >> >> > drm_dp_cec_irq(&intel_dp->aux); >> >> >> >> -- >> >> Jani Nikula, Intel >> >> -- >> Jani Nikula, Intel -- Jani Nikula, Intel