From mboxrd@z Thu Jan 1 00:00:00 1970 From: heiko@sntech.de (Heiko Stuebner) Date: Tue, 25 Sep 2018 13:18:42 +0200 Subject: [PATCH v5 2/5] drm/dp: fix link probing for devices supporting DP 1.4+ In-Reply-To: <1537866837-4408-3-git-send-email-dkos@cadence.com> References: <1537866837-4408-1-git-send-email-dkos@cadence.com> <1537866837-4408-3-git-send-email-dkos@cadence.com> Message-ID: <18095829.BFmvNaydv0@phil> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi Damian, Am Dienstag, 25. September 2018, 11:13:32 CEST schrieb Damian Kos: > From: Quentin Schulz > > DP 1.4 introduced a DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT bit in > DP_TRAINING_AUX_RD_INTERVAL register. If set, DPCD registers from > DP_DPCD_REV to DP_ADAPTER_CAP should be retrieved starting from > DP_DPCD_REV_EXTENDED. All registers are copied except DP_DPCD_REV, > DP_MAX_LINK_RATE and DP_DOWNSTREAMPORT_PRESENT which represent the > "true capabilities" of DPRX device. > > Original DP_DPCD_REV, DP_MAX_LINK_RATE and DP_DOWNSTREAMPORT_PRESENT > might falsely return lower capabilities to "avoid interoperability > issues with some of the existing DP Source devices that malfunction > when they discover the higher capabilities within those three > registers.". > > Before DP 1.4, DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT bit was reserved > and read 0 so it's safe to check against it even if DP revision is > <1.4 > > Signed-off-by: Quentin Schulz > Signed-off-by: Damian Kos in v4 you received a Reviewed-by: Manasi Navare for this patch. If a patch is largely unchanged from one version to another please add these previously received tags to the commit message. This prevents people from reviewing needlessly stuff twice ;-) . So the above should read ----- 8< ----- Signed-off-by: Quentin Schulz Signed-off-by: Damian Kos Reviewed-by: Manasi Navare ----- 8< ----- Heiko