From 3d3721ccb18a3dcec874c44120e2df7ec1c1db99 Mon Sep 17 00:00:00 2001 From: Lyude Paul Date: Wed, 26 Aug 2020 14:24:49 -0400 Subject: drm/i915/dp: Extract drm_dp_read_downstream_info() We're going to be doing the same probing process in nouveau for determining downstream DP port capabilities, so let's deduplicate the work by moving i915's code for handling this into a shared helper: drm_dp_read_downstream_info(). Note that when we do this, we also do make some functional changes while we're at it: * We always clear the downstream port info before trying to read it, just to make things easier for the caller * We skip reading downstream port info if the DPCD indicates that we don't support downstream port info * We only read as many bytes as needed for the reported number of downstream ports, no sense in reading the whole thing every time v2: * Fixup logic for calculating the downstream port length to account for the fact that downstream port caps can be either 1 byte or 4 bytes long. We can actually skip fixing the max_clock/max_bpc helpers here since they all check for DP_DETAILED_CAP_INFO_AVAILABLE anyway. * Fix ret code check for drm_dp_dpcd_read v5: * Change name from drm_dp_downstream_read_info() to drm_dp_read_downstream_info() * Also, add "See Also" sections for the various downstream info functions (drm_dp_read_downstream_info(), drm_dp_downstream_max_clock(), drm_dp_downstream_max_bpc()) Reviewed-by: Sean Paul Signed-off-by: Lyude Paul Reviewed-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/20200826182456.322681-14-lyude@redhat.com --- include/drm/drm_dp_helper.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'include/drm') diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 5c2819924862..b8716b200666 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1613,6 +1613,9 @@ int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux, bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux, u8 real_edid_checksum); +int drm_dp_read_downstream_info(struct drm_dp_aux *aux, + const u8 dpcd[DP_RECEIVER_CAP_SIZE], + u8 downstream_ports[DP_MAX_DOWNSTREAM_PORTS]); int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE], const u8 port_cap[4]); int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE], -- cgit v1.2.3