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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	stable@vger.kernel.org,
	Mario Kleiner <mario.kleiner.de@gmail.com>,
	Alex Deucher <alexander.deucher@amd.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.5 10/46] drm/amd/display: Add link_rate quirk for Apple 15" MBP 2017
Date: Tue,  7 Apr 2020 12:21:41 +0200	[thread overview]
Message-ID: <20200407101500.616555233@linuxfoundation.org> (raw)
In-Reply-To: <20200407101459.502593074@linuxfoundation.org>

From: Mario Kleiner <mario.kleiner.de@gmail.com>

[ Upstream commit dec9de2ada523b344eb2428abfedf9d6cd0a0029 ]

This fixes a problem found on the MacBookPro 2017 Retina panel:

The panel reports 10 bpc color depth in its EDID, and the
firmware chooses link settings at boot which support enough
bandwidth for 10 bpc (324000 kbit/sec aka LINK_RATE_RBR2
aka 0xc), but the DP_MAX_LINK_RATE dpcd register only reports
2.7 Gbps (multiplier value 0xa) as possible, in direct
contradiction of what the firmware successfully set up.

This restricts the panel to 8 bpc, not providing the full
color depth of the panel on Linux <= 5.5. Additionally, commit
'4a8ca46bae8a ("drm/amd/display: Default max bpc to 16 for eDP")'
introduced into Linux 5.6-rc1 will unclamp panel depth to
its full 10 bpc, thereby requiring a eDP bandwidth for all
modes that exceeds the bandwidth available and causes all modes
to fail validation -> No modes for the laptop panel -> failure
to set any mode -> Panel goes dark.

This patch adds a quirk specific to the MBP 2017 15" Retina
panel to override reported max link rate to the correct maximum
of 0xc = LINK_RATE_RBR2 to fix the darkness and reduced display
precision.

Please apply for Linux 5.6+ to avoid regressing Apple MBP panel
support.

Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
index 504055fc70e89..6f2b3ec17e7f0 100644
--- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
@@ -2909,6 +2909,17 @@ static bool retrieve_link_cap(struct dc_link *link)
 		sink_id.ieee_device_id,
 		sizeof(sink_id.ieee_device_id));
 
+	/* Quirk Apple MBP 2017 15" Retina panel: Wrong DP_MAX_LINK_RATE */
+	{
+		uint8_t str_mbp_2017[] = { 101, 68, 21, 101, 98, 97 };
+
+		if ((link->dpcd_caps.sink_dev_id == 0x0010fa) &&
+		    !memcmp(link->dpcd_caps.sink_dev_id_str, str_mbp_2017,
+			    sizeof(str_mbp_2017))) {
+			link->reported_link_cap.link_rate = 0x0c;
+		}
+	}
+
 	core_link_read_dpcd(
 		link,
 		DP_SINK_HW_REVISION_START,
-- 
2.20.1




  parent reply	other threads:[~2020-04-07 10:24 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-07 10:21 [PATCH 5.5 00/46] 5.5.16-rc1 review Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 01/46] ipv4: fix a RCU-list lock in fib_triestat_seq_show Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 02/46] net: dsa: ksz: Select KSZ protocol tag Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 03/46] net, ip_tunnel: fix interface lookup with no key Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 04/46] sctp: fix possibly using a bad saddr with a given dst Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 05/46] sctp: fix refcount bug in sctp_wfree Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 06/46] net: macb: Fix handling of fixed-link node Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 07/46] nvme-rdma: Avoid double freeing of async event data Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 08/46] staging: wfx: fix warning about freeing in-use mutex during device unregister Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 09/46] drm/amdgpu: add fbdev suspend/resume on gpu reset Greg Kroah-Hartman
2020-04-07 10:21 ` Greg Kroah-Hartman [this message]
2020-04-07 10:21 ` [PATCH 5.5 11/46] drm/bochs: downgrade pci_request_region failure from error to warning Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 12/46] initramfs: restore default compression behavior Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 13/46] drm/amdgpu: fix typo for vcn1 idle check Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 14/46] tools/power turbostat: Fix gcc build warnings Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 15/46] tools/power turbostat: Fix missing SYS_LPI counter on some Chromebooks Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 16/46] tools/power turbostat: Fix 32-bit capabilities warning Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 17/46] padata: fix uninitialized return value in padata_replace() Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 18/46] brcmfmac: abort and release host after error Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 19/46] bpf: Fix tnum constraints for 32-bit comparisons Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 20/46] XArray: Fix xa_find_next for large multi-index entries Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 21/46] misc: rtsx: set correct pcr_ops for rts522A Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 22/46] misc: pci_endpoint_test: Fix to support > 10 pci-endpoint-test devices Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 23/46] misc: pci_endpoint_test: Avoid using module parameter to determine irqtype Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 24/46] PCI: sysfs: Revert "rescan" file renames Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 25/46] coresight: do not use the BIT() macro in the UAPI header Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 26/46] mei: me: add cedar fork device ids Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 27/46] nvmem: check for NULL reg_read and reg_write before dereferencing Greg Kroah-Hartman
2020-04-07 10:21 ` [PATCH 5.5 28/46] nvmem: sprd: Fix the block lock operation Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 29/46] extcon: axp288: Add wakeup support Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 30/46] power: supply: axp288_charger: Add special handling for HP Pavilion x2 10 Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 31/46] Revert "dm: always call blk_queue_split() in dm_process_bio()" Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 32/46] ALSA: hda/ca0132 - Add Recon3Di quirk to handle integrated sound on EVGA X99 Classified motherboard Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 33/46] soc: mediatek: knows_txdone needs to be set in Mediatek CMDQ helper Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 34/46] net/mlx5e: kTLS, Fix wrong value in record tracker enum Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 35/46] iwlwifi: consider HE capability when setting LDPC Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 36/46] iwlwifi: yoyo: dont add TLV offset when reading FIFOs Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 37/46] iwlwifi: dbg: dont abort if sending DBGC_SUSPEND_RESUME fails Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 38/46] rxrpc: Fix sendmsg(MSG_WAITALL) handling Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 39/46] IB/hfi1: Ensure pq is not left on waitlist Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 40/46] sched: act: count in the size of action flags bitfield Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 41/46] tcp: fix TFO SYNACK undo to avoid double-timestamp-undo Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 42/46] i2c: i801: Do not add ICH_RES_IO_SMI for the iTCO_wdt device Greg Kroah-Hartman
2020-04-07 11:13   ` Wolfram Sang
2020-04-07 14:48     ` Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 43/46] net: genetlink: return the error code when attribute parsing fails Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 44/46] net: Fix Tx hash bound checking Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 45/46] net/smc: fix cleanup for linkgroup setup failures Greg Kroah-Hartman
2020-04-07 10:22 ` [PATCH 5.5 46/46] padata: always acquire cpu_hotplug_lock before pinst->lock Greg Kroah-Hartman
2020-04-07 12:37 ` [PATCH 5.5 00/46] 5.5.16-rc1 review Jon Hunter

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