From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 53CA413C9D4 for ; Tue, 4 Feb 2025 10:22:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738664569; cv=none; b=Qfc8FCu4ecey9i616ORW2d1t56vSVJxvCKVI+NR/NfhV48o8oKkJpA2ZfjkU6nIC7GV1190P0UFVKZfK9UzrbPTX2kBDn/txIK+xYpg/8TzRVDwRzI72AAOfnepaDPfVKQnkZHPC1OtnaF5vlFLR3gxnsmH+bSjGtZxq9svXu2A= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738664569; c=relaxed/simple; bh=gJ4o45DrQ6UM53CuzLLDKfz5ptWwJJHOyJCxE7cr04k=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=FIAVaL7y6IzZHESF7Mhb0tbRBeRbbklagAoaObidAJDm/hiWt30j7lM//PChZFWMGysHbiVVfSJ1aOZofrKmDsxffVrMLn0S4M5sItE7qZf9+kMB4Jky+KxfzoXRQMQh3sYntVFRwoQAoEwp36DlHLid9+2q/OySwY3gMGfMHag= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bitkx4R7; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="bitkx4R7" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 464DEC4CEDF; Tue, 4 Feb 2025 10:22:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1738664568; bh=gJ4o45DrQ6UM53CuzLLDKfz5ptWwJJHOyJCxE7cr04k=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=bitkx4R7lVZNmviJGnsDZFCKj5L/94jH6TLm/07+K92+81RpvqsiNJOcwsBKLA6Tb yMGz+2d5FHngQOgKbA5SE0tJwDYagwqhxAmAvnXe1MZTd6NxkFC6wSARLEMQGiUum5 RZG2ykO+e54bO5Vc1YVUSlA72bObnd3gr6T0ACZA= Date: Tue, 4 Feb 2025 11:22:45 +0100 From: Greg KH To: Wayne Lin Cc: stable@vger.kernel.org, Mario Limonciello , Alex Deucher , Jerry Zuo , Tom Chung , Daniel Wheeler Subject: Re: [PATCH 6.12.y] drm/amd/display: Reduce accessing remote DPCD overhead Message-ID: <2025020403-conjoined-murky-f8e5@gregkh> References: <2025012032-phoenix-crushing-da7a@gregkh> <20250204101336.2029586-1-Wayne.Lin@amd.com> Precedence: bulk X-Mailing-List: stable@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: <20250204101336.2029586-1-Wayne.Lin@amd.com> On Tue, Feb 04, 2025 at 06:13:36PM +0800, Wayne Lin wrote: > [Why] > Observed frame rate get dropped by tool like glxgear. Even though the > output to monitor is 60Hz, the rendered frame rate drops to 30Hz lower. > > It's due to code path in some cases will trigger > dm_dp_mst_is_port_support_mode() to read out remote Link status to > assess the available bandwidth for dsc maniplation. Overhead of keep > reading remote DPCD is considerable. > > [How] > Store the remote link BW in mst_local_bw and use end-to-end full_pbn > as an indicator to decide whether update the remote link bw or not. > > Whenever we need the info to assess the BW, visit the stored one first. > > Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/3720 > Fixes: fa57924c76d9 ("drm/amd/display: Refactor function dm_dp_mst_is_port_support_mode()") > Cc: Mario Limonciello > Cc: Alex Deucher > Reviewed-by: Jerry Zuo > Signed-off-by: Wayne Lin > Signed-off-by: Tom Chung > Tested-by: Daniel Wheeler > Signed-off-by: Alex Deucher > (cherry picked from commit 4a9a918545455a5979c6232fcf61ed3d8f0db3ae) > Cc: stable@vger.kernel.org > (cherry picked from commit adb4998f4928a17d91be054218a902ba9f8c1f93) I'm confused, which commit is this exactly? Both of these seem to be the same, and you can't have 2 "cherry picked from" lines in a commit, right? thanks, greg k-h