From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 95F7D409278; Wed, 8 Jul 2026 15:26:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783524368; cv=none; b=rTMPgHrarOQdXy8uglHDL9YVKu9kMSYcAZ+p7AN9AcEDamiFqhLMBqfT+mKlQJEAGwA7WjBpLdK86be785tS//88IJLX6iGCbTH5aka2lBUriaHCBSoB54xwNOLYMrTRVD/R8/WCiesgjvLWFKTi4p2CnFt/Cgw+Q4d4NP4pQG4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783524368; c=relaxed/simple; bh=whlFHqnb1XuOYu2Xd8sn/x0N9b/+58vwnkVIRaGYQjo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=uvIh6RO+hpmgBVCIWTDh9D9+gqqXh66+gYjz4bLV4II0bmbWx3vy9ktOMWkEoEL0kah7wdN+FlgV4f9QYnw1E81zyOX2wwTYZAUr+BeGkW0K2Oj1BpDDC6MuZUlfWsAwARNymLotJjNEQCRSW4jae4j+BrZ1x5DyhSUck+hLUV8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gDhSlbSN; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="gDhSlbSN" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2EB831F000E9; Wed, 8 Jul 2026 15:26:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783524367; bh=yVimvhatc65Owlde0V/MOtWQPfIwkXZ1GniY6IYK8AE=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=gDhSlbSNBaBZGjTVhSc1SE3KOE3xKeG78VYrDpRrru2etALr/MsRqmirN0OVpkj+B r0jxEk5eOPYRfs7gNNz20QzeEpCMd3qJLCiHIMamEUhAshXSST0xAIm2ulX+kSvuJj z0pGxmnsA4gtthbkijOWfdGOyC+iJO8S/0q2aKZl3OWK1PJ8DYq4vEFr8e2NbpLJvr ZkkZ+/D38zBTHOQlRYJUk4bpYIca2QNQ0dzRlxjeV9/7SboZhKKnpC0G5dwS6+HvQh 9PEWb92P9Tdn1mR9Aww2bI7QTMZiDDDjohTYDQbNe8iddTLQLml1O5Z4Z6RdUKl2gJ 3qF+zxxgUhNVQ== Date: Wed, 8 Jul 2026 10:26:03 -0500 From: Bjorn Andersson To: Bibek Kumar Patro Cc: Dmitry Baryshkov , Will Deacon , Robin Murphy , Joerg Roedel , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Konrad Dybcio , Rob Clark , linux-arm-kernel@lists.infradead.org, iommu@lists.linux.dev, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-msm@vger.kernel.org Subject: Re: [PATCH v3 3/6] arm64: dts: qcom: kodiak: Add GEM_NOC interconnect for adreno SMMU Message-ID: References: <20260706-smmu_interconnect_addition-v3-0-afdca0125a65@oss.qualcomm.com> <20260706-smmu_interconnect_addition-v3-3-afdca0125a65@oss.qualcomm.com> <807f145d-88d3-460a-9862-b63fe2a52cf7@oss.qualcomm.com> <4e5a3d82-b946-4490-885a-ea7061939c32@oss.qualcomm.com> Precedence: bulk X-Mailing-List: devicetree@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: <4e5a3d82-b946-4490-885a-ea7061939c32@oss.qualcomm.com> On Wed, Jul 08, 2026 at 03:31:07PM +0530, Bibek Kumar Patro wrote: > > > On 7/7/2026 10:14 PM, Dmitry Baryshkov wrote: > > On Tue, Jul 07, 2026 at 06:37:24PM +0530, Bibek Kumar Patro wrote: > > > > > > > > > On 7/6/2026 11:12 PM, Dmitry Baryshkov wrote: > > > > On Mon, Jul 06, 2026 at 10:26:36PM +0530, Bibek Kumar Patro wrote: > > > > > On Kodiak platforms, the Adreno SMMU requires a bandwidth vote on > > > > > the GEM_NOC path (MASTER_GPU_TCU -> SLAVE_EBI1) before its registers > > > > > are accessible. Without this vote, the SMMU may become unreachable, > > > > > leading to intermittent probe failures and runtime issues. > > > > > > > > > > Add the required interconnect to ensure reliable register access. > > > > > > > > > > Signed-off-by: Bibek Kumar Patro > > > > > --- > > > > > arch/arm64/boot/dts/qcom/kodiak.dtsi | 2 ++ > > > > > 1 file changed, 2 insertions(+) > > > > > > > > > > diff --git a/arch/arm64/boot/dts/qcom/kodiak.dtsi b/arch/arm64/boot/dts/qcom/kodiak.dtsi > > > > > index 90e50c245c0c..721526f023dd 100644 > > > > > --- a/arch/arm64/boot/dts/qcom/kodiak.dtsi > > > > > +++ b/arch/arm64/boot/dts/qcom/kodiak.dtsi > > > > > @@ -3389,6 +3389,8 @@ adreno_smmu: iommu@3da0000 { > > > > > power-domains = <&gpucc GPU_CC_CX_GDSC>; > > > > > dma-coherent; > > > > > + interconnects = <&gem_noc MASTER_GPU_TCU QCOM_ICC_TAG_ALWAYS > > > > > + &mc_virt SLAVE_EBI1 QCOM_ICC_TAG_ALWAYS>; > > > > > > > > Why is it ALWAYS? Would it be better to declare it as ACTIVE_ONLY and > > > > > > Added QCOM_ICC_TAG_ALWAYS, to hold the vote in SLEEP bucket as well > > > preventing gem_noc going to sleep when icc_set_bw is being called. > > > > _why_? > > > > Now when i think of where we implemented the hooks, ALWAYS is not needed. We > should keep it ACTIVE_ONLY since we are already voting it > back in resume pah. I'll fix it in next revision. > The path is between the SMMU and DDR, so clearly it has to do with the TCU's ability to fetch things from DDR. ACTIVE_ONLY states that the vote should only be applied when the application subsystem (CPUSS) is not in low-power mode (CPU is active). So, are you saying that in all cases that cpuidle might select such low-power state the GPU TCU is "stopped", and does not need to perform any memory transactions? To me these two are orthogonal and TAG_ALWAYS is logically correct, but perhaps there's some practical dependency that I'm missing? Regards, Bjorn > > > > > > > then drop the extra suspend/resume play? > > > > > > Not sure if I understood it correctly. > > > Did you mean the extra suspend/resume play in arm_smmu_runtime_suspend > > > or in arm_smmu_device_shutdown() path? > > > > runtime_suspend/resume. I might be incorrect here, but I think it is > > exactly what you need. > > > > Yes, I think we should go with the ACTIVE_ONLY flag and we would need > this voting in suspend resume path (For the same reason mentioned in commit > description and cover letter of the series). > > ALWAYS would avoid the need for this handling, it would keep the vote active > unnecessarily, but still that would have been nondeterministic. > > Thanks & regards, > Bibek > > > > > > > Thanks & regards, > > > Bibek > > > > > > > > > > > > }; > > > > > gfx_0_tbu: tbu@3dd9000 { > > > > > > > > > > -- > > > > > 2.34.1 > > > > > > > > > > > > > > >