diff options
Diffstat (limited to 'drivers/gpu/drm/display/drm_dp_mst_topology.c')
| -rw-r--r-- | drivers/gpu/drm/display/drm_dp_mst_topology.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c b/drivers/gpu/drm/display/drm_dp_mst_topology.c index 6d09bef671da..3a1f1ffc7b55 100644 --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c @@ -171,18 +171,30 @@ static const char *drm_dp_mst_sideband_tx_state_str(int state) return sideband_reason_str[state]; } +static inline u8 +drm_dp_mst_get_ufp_num_at_lct_from_rad(u8 lct, const u8 *rad) +{ + int idx = (lct / 2) - 1; + int shift = (lct % 2) ? 0 : 4; + u8 ufp_num; + + /* mst_primary, it's rad is unset*/ + if (lct == 1) + return 0; + + ufp_num = (rad[idx] >> shift) & 0xf; + + return ufp_num; +} + static int drm_dp_mst_rad_to_str(const u8 rad[8], u8 lct, char *out, size_t len) { int i; - u8 unpacked_rad[16]; + u8 unpacked_rad[16] = {}; - for (i = 0; i < lct; i++) { - if (i % 2) - unpacked_rad[i] = rad[i / 2] >> 4; - else - unpacked_rad[i] = rad[i / 2] & BIT_MASK(4); - } + for (i = 0; i < lct; i++) + unpacked_rad[i] = drm_dp_mst_get_ufp_num_at_lct_from_rad(i + 1, rad); /* TODO: Eventually add something to printk so we can format the rad * like this: 1.2.3 @@ -2544,9 +2556,8 @@ static struct drm_dp_mst_branch *drm_dp_get_mst_branch_device(struct drm_dp_mst_ if (!mstb) goto out; - for (i = 0; i < lct - 1; i++) { - int shift = (i % 2) ? 0 : 4; - int port_num = (rad[i / 2] >> shift) & 0xf; + for (i = 1; i < lct; i++) { + int port_num = drm_dp_mst_get_ufp_num_at_lct_from_rad(i + 1, rad); list_for_each_entry(port, &mstb->ports, next) { if (port->port_num == port_num) { |