From: Tom Rix <t...@redhat.com>

[ Upstream commit cdd296cdae1af2d27dae3fcfbdf12c5252ab78cf ]

Reviewing this block of code in cdv_intel_dp_init()

ret = cdv_intel_dp_aux_native_read(gma_encoder, DP_DPCD_REV, ...

cdv_intel_edp_panel_vdd_off(gma_encoder);
if (ret == 0) {
        /* if this fails, presume the device is a ghost */
        DRM_INFO("failed to retrieve link info, disabling eDP\n");
        drm_encoder_cleanup(encoder);
        cdv_intel_dp_destroy(connector);
        goto err_priv;
} else {

The (ret == 0) is not strict enough.
cdv_intel_dp_aux_native_read() returns > 0 on success
otherwise it is failure.

So change to <=

Fixes: d112a8163f83 ("gma500/cdv: Add eDP support")

Signed-off-by: Tom Rix <t...@redhat.com>
Signed-off-by: Patrik Jakobsson <patrik.r.jakobs...@gmail.com>
Link: 
https://patchwork.freedesktop.org/patch/msgid/20200805205911.20927-1-t...@redhat.com
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 drivers/gpu/drm/gma500/cdv_intel_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/gma500/cdv_intel_dp.c 
b/drivers/gpu/drm/gma500/cdv_intel_dp.c
index 90ed20083009f..05eba6dec5ebf 100644
--- a/drivers/gpu/drm/gma500/cdv_intel_dp.c
+++ b/drivers/gpu/drm/gma500/cdv_intel_dp.c
@@ -2119,7 +2119,7 @@ cdv_intel_dp_init(struct drm_device *dev, struct 
psb_intel_mode_device *mode_dev
                                               intel_dp->dpcd,
                                               sizeof(intel_dp->dpcd));
                cdv_intel_edp_panel_vdd_off(gma_encoder);
-               if (ret == 0) {
+               if (ret <= 0) {
                        /* if this fails, presume the device is a ghost */
                        DRM_INFO("failed to retrieve link info, disabling 
eDP\n");
                        cdv_intel_dp_encoder_destroy(encoder);
-- 
2.25.1



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