[PATCH v2] drm/i915: Don't read dpcd for disconnected ports

[Jani Nikula <jani.nikula@intel.com>]

From: Mika Kuoppala <mika.kuoppala@linux.intel.com>

Reading from disconnected ports will spit out timeout error
on the dmesg. Skip the attempted read if the port is not
connected and avoid confusing users/testcases about
expected timeouts.

This new dpcd debugfs entry was introduced by commit aa7471d228eb
("drm/i915: add i915 specific connector debugfs file for DPCD")

v2 by Jani: move the check at the top, out of the loop.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=90060
Tested-by: yex.tian@intel.com
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Bob Paauwe <bob.j.paauwe@intel.com>
Signed-off-by: Mika Kuoppala <mika.kuoppala@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/i915/i915_debugfs.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
index adbbddab42c6..a32b669bab89 100644
--- a/drivers/gpu/drm/i915/i915_debugfs.c
+++ b/drivers/gpu/drm/i915/i915_debugfs.c
@@ -5154,6 +5154,9 @@ static int i915_dpcd_show(struct seq_file *m, void *data)
 	ssize_t err;
 	int i;
 
+	if (connector->status != connector_status_connected)
+		return -ENODEV;
+
 	for (i = 0; i < ARRAY_SIZE(i915_dpcd_debug); i++) {
 		const struct dpcd_block *b = &i915_dpcd_debug[i];
 		size_t size = b->end ? b->end - b->offset + 1 : (b->size ?: 1);
-- 
2.1.4

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