Methods, systems, and devices for wireless communications are described. A user equipment (UE) may receive, from a base station, a control message indicating a resource configuration for uplink and downlink transmissions. The UE may determine an uplink buffer threshold for a modem buffer of the UE based on the resource configuration. The UE may transmit, to the base station, a feedback request message requesting that the base station provide feedback for at least one previously transmitted uplink packet based on a comparison of an amount of previously transmitted uplink data and scheduled uplink data stored in the modem buffer relative to the uplink buffer threshold. The UE may receive, based on transmitting the feedback request message, a feedback response message corresponding to a first previously transmitted uplink packet of the at least one previously transmitted uplink packet.