> Whenever the UART device driver gets closed from userland, the driver > disables the UART unit and then stops its clock to save power. > > The bit which disabled the UART unit is described as: > > "UART Enable. If this bit is set to 1, the UART is enabled. Data > transmission and reception occurs for the UART signals. When the > UART is disabled in the middle of transmission or reception, it > completes the current character before stopping." > > The important part is the "it completes the current character". Whenever > a reception is ongoing when the UART gets disabled (including the clock > off) the statemachine freezes and "remembers" this state on the next > open() and re-enabling of the unit's clock. > > In this case we end up receiving an additional bogus character > immediately. > > The solution in this change is to move the AUART unit into its reset > state on close() and only release it from its reset state on the next > open(). > > Signed-off-by: Juergen Borleis <j...@pengutronix.de> > ---
Acked-by: Stefan Wahren <stefan.wah...@i2se.com> Thanks Stefan -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
