On Mon, May 13, 2024 at 04:39:22PM +0200, Ronald Wahl wrote: > From: Ronald Wahl <ronald.wahl@xxxxxxxxxxx> > > Under some circumstances it may happen that the ks8851 Ethernet driver > stops sending data. > > Currently the interrupt handler resets the interrupt status flags in the > hardware after handling TX. With this approach we may lose interrupts in > the time window between handling the TX interrupt and resetting the TX > interrupt status bit. > > When all of the three following conditions are true then transmitting > data stops: > > - TX queue is stopped to wait for room in the hardware TX buffer > - no queued SKBs in the driver (txq) that wait for being written to hw > - hardware TX buffer is empty and the last TX interrupt was lost > > This is because reenabling the TX queue happens when handling the TX > interrupt status but if the TX status bit has already been cleared then > this interrupt will never come. > > With this commit the interrupt status flags will be cleared before they > are handled. That way we stop losing interrupts. > > The wrong handling of the ISR flags was there from the beginning but > with commit 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX > buffer overrun") the issue becomes apparent. > > Fixes: 3dc5d4454545 ("net: ks8851: Fix TX stall caused by TX buffer overrun") > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: Eric Dumazet <edumazet@xxxxxxxxxx> > Cc: Jakub Kicinski <kuba@xxxxxxxxxx> > Cc: Paolo Abeni <pabeni@xxxxxxxxxx> > Cc: Simon Horman <horms@xxxxxxxxxx> > Cc: netdev@xxxxxxxxxxxxxxx > Cc: stable@xxxxxxxxxxxxxxx # 5.10+ > Signed-off-by: Ronald Wahl <ronald.wahl@xxxxxxxxxxx> Reviewed-by: Simon Horman <horms@xxxxxxxxxx>