drm/i915: Filter out glitches on HPD lines during hotplug detection

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Glitches deasserting the connector HPD line can lead to incorrectly
detecting a disconnect event (a glitch asserting the line will only
cause a redundant connect->disconnect transition). The source of such a
glitch can be noise on the line or a 0.5ms-1ms MST IRQ_HPD pulse. TypeC
ports in the DP-alt or TBT-alt mode filter out these glitches inernally,
but for others the driver has to do this. Make it so by polling the HPD
line on these connectors for 4 ms.

Link: https://patchwork.freedesktop.org/patch/msgid/20240104083008.2715733-12-imre.deak@intel.com
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>

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This commit is contained in:

Imre Deak 2024-01-04 10:30:07 +02:00

parent 9210e94a5a

commit 2e4b90fbe7

3 changed files with 21 additions and 2 deletions

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13

drivers/gpu/drm/i915/display/intel_dp.c

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9

drivers/gpu/drm/i915/display/intel_tc.c

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1

drivers/gpu/drm/i915/display/intel_tc.h

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