From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sasha Levin Subject: [PATCH AUTOSEL 5.1 040/141] drm/amd/display: set link->dongle_max_pix_clk to 0 on a disconnect Date: Fri, 19 Jul 2019 00:01:05 -0400 Message-ID: <20190719040246.15945-40-sashal@kernel.org> References: <20190719040246.15945-1-sashal@kernel.org> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20190719040246.15945-1-sashal@kernel.org> Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Samson Tam , Jun Lei , Bhawanpreet Lakha , Alex Deucher , Sasha Levin , amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org List-Id: amd-gfx.lists.freedesktop.org From: Samson Tam [ Upstream commit 233d87a579b8adcc6da5823fa507ecb6675e7562 ] [Why] Found issue in EDID Emulation where if we connect a display using a passive HDMI-DP dongle, disconnect it and then try to emulate a display using DP, we could not see 4K modes. This was because on a disconnect, dongle_max_pix_clk was still set so when we emulate using DP, in dc_link_validate_mode_timing(), it would think we were still using a dongle and limit the modes we support. [How] In dc_link_detect(), set dongle_max_pix_clk to 0 when we detect a hotplug out ( if new_connection_type = dc_connection_none ). Signed-off-by: Samson Tam Reviewed-by: Jun Lei Acked-by: Bhawanpreet Lakha Signed-off-by: Alex Deucher Signed-off-by: Sasha Levin --- drivers/gpu/drm/amd/display/dc/core/dc_link.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c index 6072636da388..1367e2679082 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c @@ -922,6 +922,12 @@ bool dc_link_detect(struct dc_link *link, enum dc_detect_reason reason) link->type = dc_connection_none; sink_caps.signal = SIGNAL_TYPE_NONE; + /* When we unplug a passive DP-HDMI dongle connection, dongle_max_pix_clk + * is not cleared. If we emulate a DP signal on this connection, it thinks + * the dongle is still there and limits the number of modes we can emulate. + * Clear dongle_max_pix_clk on disconnect to fix this + */ + link->dongle_max_pix_clk = 0; } LINK_INFO("link=%d, dc_sink_in=%p is now %s prev_sink=%p dpcd same=%d edid same=%d\n", -- 2.20.1