This is a note to let you know that I've just added the patch titled drm/radeon/ci: disable mclk switching for high refresh rates (v2) to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: drm-radeon-ci-disable-mclk-switching-for-high-refresh-rates-v2.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From ab03d9fe508f4e2914a8f4a9eef1b21051cacd0f Mon Sep 17 00:00:00 2001 From: Alex Deucher <alexander.deucher@xxxxxxx> Date: Thu, 11 May 2017 13:14:14 -0400 Subject: drm/radeon/ci: disable mclk switching for high refresh rates (v2) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Alex Deucher <alexander.deucher@xxxxxxx> commit ab03d9fe508f4e2914a8f4a9eef1b21051cacd0f upstream. Even if the vblank period would allow it, it still seems to be problematic on some cards. v2: fix logic inversion (Nils) bug: https://bugs.freedesktop.org/show_bug.cgi?id=96868 Acked-by: Christian König <christian.koenig@xxxxxxx> Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/gpu/drm/radeon/ci_dpm.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/drivers/gpu/drm/radeon/ci_dpm.c +++ b/drivers/gpu/drm/radeon/ci_dpm.c @@ -738,6 +738,12 @@ bool ci_dpm_vblank_too_short(struct rade if (r600_dpm_get_vrefresh(rdev) > 120) return true; + /* disable mclk switching if the refresh is >120Hz, even if the + * blanking period would allow it + */ + if (r600_dpm_get_vrefresh(rdev) > 120) + return true; + if (vblank_time < switch_limit) return true; else Patches currently in stable-queue which might be from alexander.deucher@xxxxxxx are queue-3.18/drm-radeon-ci-disable-mclk-switching-for-high-refresh-rates-v2.patch