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 337A4C4332F for ; Thu, 15 Dec 2022 10:30:47 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 0E50710E518; Thu, 15 Dec 2022 10:30:46 +0000 (UTC) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by gabe.freedesktop.org (Postfix) with ESMTPS id 38DED10E518 for ; Thu, 15 Dec 2022 10:30:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1671100241; x=1702636241; h=from:to:cc:subject:in-reply-to:references:date: message-id:mime-version; bh=kZ4RmLCjhj2JTM5rqHpHfTBZKaBBYqwOC4Av8r28FDY=; b=K2D9bBkwLqShhkkmq2yRiwq2UbQ4be5fLOOPtAdewqZ8z3zBWKPW2AlM iNpFdM0WxFiRHHaIHpQPTBvhMi4Jrow0x4uxXaBCReClAhZ3hkXIR0K7K 84kHboB+jybqR6dpk8NyDXPtlumh7mTPqZbN2781OAfiy/KUoLRHIurqU VTHqxuUmBJLBIkT5q74k2PNRhupQ4v3muCPaxD8QNDBCbIhNWgqraMV3q S5WYXSJdTPQQzD7SsuAol0MrV5Z7ZhHVEyuYvCpnuuiBeyRvsURWbR4aH 0ryxW89wGk9y8C1xdZtEYtzj6dTEmvmuE5bcmAKnA9InpxztrzJNL+bIq A==; X-IronPort-AV: E=McAfee;i="6500,9779,10561"; a="319784220" X-IronPort-AV: E=Sophos;i="5.96,247,1665471600"; d="scan'208";a="319784220" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Dec 2022 02:30:31 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10561"; a="680058104" X-IronPort-AV: E=Sophos;i="5.96,247,1665471600"; d="scan'208";a="680058104" Received: from tgodea-mobl.ger.corp.intel.com (HELO localhost) ([10.252.61.26]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Dec 2022 02:30:29 -0800 From: Jani Nikula To: Arun R Murthy , intel-gfx@lists.freedesktop.org, ville.syrjala@linux.intel.com, imre.deak@intel.com In-Reply-To: <20221215095533.1073528-1-arun.r.murthy@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo References: <20221124070925.3834910-1-arun.r.murthy@intel.com> <20221215095533.1073528-1-arun.r.murthy@intel.com> Date: Thu, 15 Dec 2022 12:30:26 +0200 Message-ID: <87pmclufgd.fsf@intel.com> MIME-Version: 1.0 Content-Type: text/plain Subject: Re: [Intel-gfx] [PATCHv6] drm/i915/dp: change aux_ctl reg read to polling read X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Thu, 15 Dec 2022, Arun R Murthy wrote: > The busy timeout logic checks for the AUX BUSY, then waits for the > timeout period and then after timeout reads the register for BUSY or > Success. > Instead replace interrupt with polling so as to read the AUX CTL > register often before the timeout period. Looks like there might be some > issue with interrupt-on-read. Hence changing the logic to polling read. > > v2: replace interrupt with polling read > v3: use usleep_rang instead of msleep, updated commit msg > v4: use intel_wait_for_regiter internal function > v5: use __intel_de_wait_for_register with 500us slow and 10ms fast timeout > v6: check return value of __intel_de_wait_for_register > > Signed-off-by: Arun R Murthy > --- > drivers/gpu/drm/i915/display/intel_dp_aux.c | 15 +++++---------- > 1 file changed, 5 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c > index 91c93c93e5fc..dec88f41380e 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c > @@ -40,21 +40,16 @@ intel_dp_aux_wait_done(struct intel_dp *intel_dp) > struct drm_i915_private *i915 = dp_to_i915(intel_dp); > i915_reg_t ch_ctl = intel_dp->aux_ch_ctl_reg(intel_dp); > const unsigned int timeout_ms = 10; > - u32 status; > - bool done; > - > -#define C (((status = intel_de_read_notrace(i915, ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0) > - done = wait_event_timeout(i915->display.gmbus.wait_queue, C, > - msecs_to_jiffies_timeout(timeout_ms)); > + u32 status, ret; > > - /* just trace the final value */ > - trace_i915_reg_rw(false, ch_ctl, status, sizeof(status), true); > + ret = __intel_de_wait_for_register(i915, ch_ctl, > + DP_AUX_CH_CTL_SEND_BUSY, 0, > + 500, timeout_ms, &status); > > - if (!done) > + if (ret == -ETIMEDOUT) What's wrong with this comparison? Although it probably does work by coincidence. BR, Jani. > drm_err(&i915->drm, > "%s: did not complete or timeout within %ums (status 0x%08x)\n", > intel_dp->aux.name, timeout_ms, status); > -#undef C > > return status; > } -- Jani Nikula, Intel Open Source Graphics Center