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drm/bridge: it6505: fix HDCP V match check is not performed correctly
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[ Upstream commit a5072fc ]

Fix a typo where V compare incorrectly compares av[] with av[] itself,
which can result in HDCP failure.

The loop of V compare is expected to iterate for 5 times
which compare V array form av[0][] to av[4][].
It should check loop counter reach the last statement "i == 5"
before return true

Fixes: 0989c02 ("drm/bridge: it6505: fix HDCP CTS compare V matching")
Signed-off-by: Hermes Wu <Hermes.wu@ite.com.tw>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20250121-fix-hdcp-v-comp-v4-1-185f45c728dc@ite.com.tw
Signed-off-by: Sasha Levin <sashal@kernel.org>
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Hermes Wu authored and Greg Kroah-Hartman committed Apr 10, 2025
1 parent c3b8e7c commit d360c02
Showing 1 changed file with 4 additions and 3 deletions.
7 changes: 4 additions & 3 deletions drivers/gpu/drm/bridge/ite-it6505.c
Original file line number Diff line number Diff line change
Expand Up @@ -2039,12 +2039,13 @@ static bool it6505_hdcp_part2_ksvlist_check(struct it6505 *it6505)
continue;
}

for (i = 0; i < 5; i++) {
for (i = 0; i < 5; i++)
if (bv[i][3] != av[i][0] || bv[i][2] != av[i][1] ||
av[i][1] != av[i][2] || bv[i][0] != av[i][3])
bv[i][1] != av[i][2] || bv[i][0] != av[i][3])
break;

DRM_DEV_DEBUG_DRIVER(dev, "V' all match!! %d, %d", retry, i);
if (i == 5) {
DRM_DEV_DEBUG_DRIVER(dev, "V' all match!! %d", retry);
return true;
}
}
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