| Message ID | 20241011173356.870883-3-jm@ti.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Misc OMAP GPIO/UART fixes | expand |
Judith Mendez <jm@ti.com> writes: > Currently in omap_8250_shutdown, the dma->rx_running > flag is set to zero in omap_8250_rx_dma_flush. Next > pm_runtime_get_sync is called, which is a runtime > resume call stack which can re-set the flag. When the > call omap_8250_shutdown returns, the flag is expected > to be UN-SET, but this is not the case. This is causing > issues the next time UART is re-opened and omap_8250_rx_dma > is called. Fix by moving pm_runtime_get_sync before the > omap_8250_rx_dma_flush. > > Signed-off-by: Bin Liu <b-liu@ti.com> > Signed-off-by: Judith Mendez <jm@ti.com> Reviewed-by: Kevin Hilman <khilman@baylibre.com> Tested-by: Kevin Hilman <khilman@baylibre.com> Gave this a quick boot test on am335x-boneblack and am57xx-beagle-x15. I realize that doesn't really test the DMA paths involved here, but at least it doesn't break basic boot to serial console, and the change looks coorect. Thanks for sending a fix for this. Kevin
On Fri, Oct 11, 2024 at 12:33:56PM -0500, Judith Mendez wrote: > Currently in omap_8250_shutdown, the dma->rx_running > flag is set to zero in omap_8250_rx_dma_flush. Next > pm_runtime_get_sync is called, which is a runtime > resume call stack which can re-set the flag. When the > call omap_8250_shutdown returns, the flag is expected > to be UN-SET, but this is not the case. This is causing > issues the next time UART is re-opened and omap_8250_rx_dma > is called. Fix by moving pm_runtime_get_sync before the > omap_8250_rx_dma_flush. You can go to 72 columns :) > Signed-off-by: Bin Liu <b-liu@ti.com> > Signed-off-by: Judith Mendez <jm@ti.com> Wait, who wrote this, Bin? If so, there needs to be a "From:" line saying so. What commit id does this fix? Do you want it backported to older kernels? Why mix two different subsystems in the same patch series, who is supposed to take it? thanks, greg k-h
Am Fri, 11 Oct 2024 12:33:56 -0500 schrieb Judith Mendez <jm@ti.com>: > Currently in omap_8250_shutdown, the dma->rx_running > flag is set to zero in omap_8250_rx_dma_flush. Next > pm_runtime_get_sync is called, which is a runtime > resume call stack which can re-set the flag. When the > call omap_8250_shutdown returns, the flag is expected > to be UN-SET, but this is not the case. This is causing > issues the next time UART is re-opened and omap_8250_rx_dma > is called. Fix by moving pm_runtime_get_sync before the > omap_8250_rx_dma_flush. > > Signed-off-by: Bin Liu <b-liu@ti.com> > Signed-off-by: Judith Mendez <jm@ti.com> Is this a theorectical problem or some real practical problem? So you are running a system with runtime pm enabled on serial console. How did you come across this issue? I could run the serial console/getty with runtime pm autosuspend enabled without issues all the years. Regards, Andreas
Am Sun, 13 Oct 2024 21:52:05 -0500 schrieb Bin Liu <binmlist@gmail.com>: > Hi, > > Somehow this email wasn’t cc’d to my company email account > b-liu@ti.com, so I am replying from my personal email which > subscribed to the mailing list, and sorry if the formatting is wrong > since I am writing this response on my phone. > > On Oct 12, 2024, at 7:27 AM, Andreas Kemnade <andreas@kemnade.info> > wrote: > > > > Am Fri, 11 Oct 2024 12:33:56 -0500 > > schrieb Judith Mendez <jm@ti.com>: > > > > Currently in omap_8250_shutdown, the dma->rx_running > >> flag is set to zero in omap_8250_rx_dma_flush. Next > >> pm_runtime_get_sync is called, which is a runtime > >> resume call stack which can re-set the flag. When the > >> call omap_8250_shutdown returns, the flag is expected > >> to be UN-SET, but this is not the case. This is causing > >> issues the next time UART is re-opened and omap_8250_rx_dma > >> is called. Fix by moving pm_runtime_get_sync before the > >> omap_8250_rx_dma_flush. > >> > >> Signed-off-by: Bin Liu <b-liu@ti.com> > >> Signed-off-by: Judith Mendez <jm@ti.com> > >> > > Is this a theorectical problem or some real practical problem? > > So you are running a system with runtime pm enabled on serial > > console. > > How did you come across this issue? > > I could run the serial console/getty with runtime pm autosuspend > > enabled without issues all the years. > > > Yes this is a real issue reported on AM335x. Please see the report > linked below. > > PROCESSOR-SDK-AM335X: Possible bug in 8250_omap UART driver - > Processors forum - Processors - TI E2E support forums e2e.ti.com > > Thanks for information, so it looks like material for backporting. Maybe add the link in the description and add the cc stable and add back the fixes tag. Regards, Andreas
Hi Greg, On 10/12/24 3:03 AM, Greg KH wrote: > On Fri, Oct 11, 2024 at 12:33:56PM -0500, Judith Mendez wrote: >> Currently in omap_8250_shutdown, the dma->rx_running >> flag is set to zero in omap_8250_rx_dma_flush. Next >> pm_runtime_get_sync is called, which is a runtime >> resume call stack which can re-set the flag. When the >> call omap_8250_shutdown returns, the flag is expected >> to be UN-SET, but this is not the case. This is causing >> issues the next time UART is re-opened and omap_8250_rx_dma >> is called. Fix by moving pm_runtime_get_sync before the >> omap_8250_rx_dma_flush. > > You can go to 72 columns :) ok, will fix, thanks! > >> Signed-off-by: Bin Liu <b-liu@ti.com> >> Signed-off-by: Judith Mendez <jm@ti.com> > > Wait, who wrote this, Bin? If so, there needs to be a "From:" line > saying so. I did not realize I could create a patch for someone, apologies, I will be sending v3 with correct "From:". > > What commit id does this fix? Do you want it backported to older > kernels? Why mix two different subsystems in the same patch series, who > is supposed to take it? I suppose it should be backported to older kernels so I will add back the fixes tag. Apologies for sending two different subsystems in one series, I thought describing as "misc" would be good enough to mix the two, but I can separate the patches and respin. Thanks. ~ Judith > > thanks, > > greg k-h
diff --git a/drivers/tty/serial/8250/8250_omap.c b/drivers/tty/serial/8250/8250_omap.c index 88b58f44e4e9..0dd68bdbfbcf 100644 --- a/drivers/tty/serial/8250/8250_omap.c +++ b/drivers/tty/serial/8250/8250_omap.c @@ -776,12 +776,12 @@ static void omap_8250_shutdown(struct uart_port *port) struct uart_8250_port *up = up_to_u8250p(port); struct omap8250_priv *priv = port->private_data; + pm_runtime_get_sync(port->dev); + flush_work(&priv->qos_work); if (up->dma) omap_8250_rx_dma_flush(up); - pm_runtime_get_sync(port->dev); - serial_out(up, UART_OMAP_WER, 0); if (priv->habit & UART_HAS_EFR2) serial_out(up, UART_OMAP_EFR2, 0x0);