On Fri, 2016-08-05 at 08:58 +0200, Uwe Kleine-König wrote: > On Fri, Aug 05, 2016 at 12:44:23AM +0200, Christoph Fritz wrote: > > here on a imx6sx board newly introduced DSR-irq-handling breaks serial > > console and network support. > > > > Reverting commit 27e16501052e5341934d3 "serial: imx: implement DSR irq > > handling for DTE mode" fixes the issue. > > > > The underlying cause is the RMII network configuration where register > > bit SION in IOMUXC_SW_MUX_CTL_PAD_ENET1_TX_CLK is necessary. But this > > also falsely feeds signal UART1_DTR_B and triggers DSR irq... > > > > Can we revert this commit or add a quirk for RMII-SION configs or make > > this optional by a device tree option? > > Hmm, MX6SX_PAD_ENET1_TX_CLK__ENET1_TX_CLK in > arch/arm/boot/dts/imx6sx-pinfunc.h doesn't have SION set. > > I remember there were issues around eth and SION on i.MX6DL, but don't > know the details. A quick net research found > https://community.nxp.com/thread/359531 which has: "Set the SION bit. > Note that this is not required because the funtion setting controls the > signal path, but it is good practice as it reminds the user that the > clock needs to fed back into the Ethernet MAC.". Sounds like dangerous > smattering and a wrong expectation about "users". > > https://community.nxp.com/thread/376821 is from someone who has the same > problem(?) on i.MX6SX, but no solution yet. > > Does that mean MX6SX_PAD_ENET1_TX_CLK__ENET1_TX_CLK always needs the > SION bit set? SION is necessary for pinconfig MX6SX_PAD_ENET1_TX_CLK__ENET1_REF_CLK1 if bit 17 in IOMUXC_GPR_GPR1 is set and bit 13 not. So that ref_enetpll1 provides a clock not only for the external PHY but also for the internal controller. Using SION is a quirk here, because the silicon doesn't feed the clock back to the internal controller automatically. On the other hand, NXP could argue: You need to add a wire on your PCB between ENET1_REF_CLK1 and ENET1_TX_CLK -- but referring to the datasheet ENET1_TX_CLK isn't used in RMII config... So if Fabio or Shawn agrees with my assumption above, I'll add something like 27e16501052e5341934d3 "serial: imx: implement DSR irq handling for DTE mode". Okay? -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
