• Emmanuel Grumbach's avatar
    iwlwifi: don't count the tfds in HW queue any more · eb9a372a
    Emmanuel Grumbach authored
    Since packets sent to an RA / TID in AGG are sent from a
    separate HW Tx queue, we may get into a race:
    the regular queue isn't empty while we already begin to
    send packets from the AGG queue. This would result in sending
    packets out of order.
    
    In order to cope with this, mac80211 waits until the driver
    reports that the legacy queue is drained before it can send
    packets to the AGG queue. During that time, mac80211 buffers
    packets for the driver. These packets will be sent in order
    after the driver reports it is ready.
    
    The way this was implemented in the driver is as follows:
    We held a counter that monitors the number of packets for
    an RA / TID in the HW queues. When this counter reached 0,
    we knew that the HW queues were drained and we reported to
    mac80211 that were ready to proceed.
    
    This patch changes the implementation described above. We
    now remember what is the wifi sequence number of the first
    packet that will be sent in the AGG queue (lets' call it
    ssn). When we reclaim the packet before ssn, we know that
    the queue is drained, and we are ready to proceed.
    
    This will allow us to move this logic in the upper layer and
    eventually remove the tid_data from the shared area.
    Signed-off-by: default avatarEmmanuel Grumbach <emmanuel.grumbach@intel.com>
    Signed-off-by: default avatarWey-Yi Guy <wey-yi.w.guy@intel.com>
    eb9a372a
iwl-trans-pcie-tx.c 32.1 KB