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| Started by | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| First post | 2016-05-17 03:30 +0200 |
| Last post | 2016-05-17 03:30 +0200 |
| Articles | 1 — 1 participant |
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[PATCH 4.5 081/101] drm/radeon: fix DP link training issue with second 4K monitor Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-05-17 03:30 +0200
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Date | 2016-05-17 03:30 +0200 |
| Subject | [PATCH 4.5 081/101] drm/radeon: fix DP link training issue with second 4K monitor |
| Message-ID | <rzBZD-6iF-5@gated-at.bofh.it> |
4.5-stable review patch. If anyone has any objections, please let me know. ------------------ From: Arindam Nath <arindam.nath@amd.com> commit 1a738347df2ee4977459a8776fe2c62196bdcb1b upstream. There is an issue observed when we hotplug a second DP 4K monitor to the system. Sometimes, the link training fails for the second monitor after HPD interrupt generation. The issue happens when some queued or deferred transactions are already present on the AUX channel when we initiate a new transcation to (say) get DPCD or during link training. We set AUX_IGNORE_HPD_DISCON bit in the AUX_CONTROL register so that we can ignore any such deferred transactions when a new AUX transaction is initiated. Signed-off-by: Arindam Nath <arindam.nath@amd.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/gpu/drm/radeon/radeon_dp_auxch.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/gpu/drm/radeon/radeon_dp_auxch.c +++ b/drivers/gpu/drm/radeon/radeon_dp_auxch.c @@ -105,7 +105,7 @@ radeon_dp_aux_transfer_native(struct drm tmp &= AUX_HPD_SEL(0x7); tmp |= AUX_HPD_SEL(chan->rec.hpd); - tmp |= AUX_EN | AUX_LS_READ_EN; + tmp |= AUX_EN | AUX_LS_READ_EN | AUX_HPD_DISCON(0x1); WREG32(AUX_CONTROL + aux_offset[instance], tmp);
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