4.9-stable review patch. If anyone has any objections, please let me know.
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From: Andrey Gusakov andrey.gusakov@cogentembedded.com
[ Upstream commit cffd2b16c01c3431a7a7dd62e722af33490fc436 ]
Do not fail data rates higher than 2.7 and more than 2 lanes. Try to fall back to 2.7Gbps and 2 lanes.
Acked-by: Philipp Zabel p.zabel@pengutronix.de Reviewed-by: Andrzej Hajda a.hajda@samsung.com Signed-off-by: Andrey Gusakov andrey.gusakov@cogentembedded.com Signed-off-by: Andrzej Hajda a.hajda@samsung.com Link: https://patchwork.freedesktop.org/patch/msgid/1510073785-16108-2-git-send-em... Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpu/drm/bridge/tc358767.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
--- a/drivers/gpu/drm/bridge/tc358767.c +++ b/drivers/gpu/drm/bridge/tc358767.c @@ -603,8 +603,15 @@ static int tc_get_display_props(struct t ret = drm_dp_link_probe(&tc->aux, &tc->link.base); if (ret < 0) goto err_dpcd_read; - if ((tc->link.base.rate != 162000) && (tc->link.base.rate != 270000)) - goto err_dpcd_inval; + if (tc->link.base.rate != 162000 && tc->link.base.rate != 270000) { + dev_dbg(tc->dev, "Falling to 2.7 Gbps rate\n"); + tc->link.base.rate = 270000; + } + + if (tc->link.base.num_lanes > 2) { + dev_dbg(tc->dev, "Falling to 2 lanes\n"); + tc->link.base.num_lanes = 2; + }
ret = drm_dp_dpcd_readb(&tc->aux, DP_MAX_DOWNSPREAD, tmp); if (ret < 0) @@ -637,9 +644,6 @@ static int tc_get_display_props(struct t err_dpcd_read: dev_err(tc->dev, "failed to read DPCD: %d\n", ret); return ret; -err_dpcd_inval: - dev_err(tc->dev, "invalid DPCD\n"); - return -EINVAL; }
static int tc_set_video_mode(struct tc_data *tc, struct drm_display_mode *mode)