drm/amd/display: fix resume hang because of DP short pulse

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There is a hard hang observed during resume from S3 when
the system receives a DP short pulse interrupt. This is
because there are two code paths contending for GPIO
access for AUX channel transactions. One such path is
through amdgpu_dm_display_resume() function which is
invoked from the regular system resume code path. The
other path is through handle_hpd_rx_irq(), which is
invoked in response to system receiving DP short pulse
interrupt. handle_hpd_rx_irq() guards against conflicting
GPIO access using hpd_lock, but the GPIO access from
amdgpu_dm_display_resume() remains unguarded.

This patch makes sure we use hpd_lock inside
amdgpu_dm_display_resume() to avoid race conditions
for GPIO access.

Signed-off-by: Arindam Nath <arindam.nath@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

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Arindam Nath 2017-04-26 17:39:56 +05:30 • committed by Alex Deucher

parent ba624cddbc

commit 03ea364c8e

1 changed files with 2 additions and 0 deletions

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drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c

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