Revert "serial: 8250_dma: don't bother DMA with small transfers"

PATCH Superseded Frederic Danis 4 participants 7 messages Oct 6, 2015 – Oct 9, 2015

Subsystems (2)

Bluetooth drivers TTY layer and serial drivers

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Frederic Danis

author

2015-10-06 13:08 UTC #0 lore raw

PATCH v2 1/1 Revert "serial: 8250_dma: don't bother DMA with small transfers"

This reverts commit 9119fba0cfeda6d415c9f068df66838a104b87cb.

This commit prevents from sending "big" file using Bluetooth. When sending a lot of data quickly through the Bluetooth interface, and after a variable amount of data sent, transfer fails with error:

    kernel: [  415.247453] Bluetooth: hci0 hardware error 0x00

Found on T100TA.

After reverting this commit, send works fine for any file size.

Signed-off-by Frederic Danis <[email protected]>

---
v2: Re-send to correct people

 drivers/tty/serial/8250/8250_dma.c | 4 ----
 1 file changed, 4 deletions(-)

drivers/tty/serial/8250/8250_dma.c +0 -4

index b503071..78259d3 100644
@@ -77,10 +77,6 @@ int serial8250_tx_dma(struct uart_8250_port *p)
 		return 0;
 
 	dma->tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
-	if (dma->tx_size < p->port.fifosize) {
-		ret = -EINVAL;
-		goto err;
-	}
 
 	desc = dmaengine_prep_slave_single(dma->txchan,
 					   dma->tx_addr + xmit->tail,

Signature · 1 line

1.9.1

Greg KH

maintainer

2015-10-06 13:55 UTC #1 lore raw

Quoted 9 lines · Frederic Danis

This reverts commit 9119fba0cfeda6d415c9f068df66838a104b87cb.
This commit prevents from sending "big" file using Bluetooth. When sending a lot of data quickly through the Bluetooth interface, and after a variable amount of data sent, transfer fails with error:
    kernel: [  415.247453] Bluetooth: hci0 hardware error 0x00
Found on T100TA.

Quoted 8 lines

After reverting this commit, send works fine for any file size.
Signed-off-by Frederic Danis <[email protected]>
---
v2: Re-send to correct people
 drivers/tty/serial/8250/8250_dma.c | 4 ----
 1 file changed, 4 deletions(-)

Andy, any objections?

Frederic, don't you want to see this backported to 4.0 and newer?

thanks,

greg k-h

Frederic Danis

author

2015-10-06 14:23 UTC #2 lore raw

Hello Greg,

Quoted 16 lines · Greg KH

Quoted 15 lines · Frederic Danis
This reverts commit 9119fba0cfeda6d415c9f068df66838a104b87cb.
This commit prevents from sending "big" file using Bluetooth. When sending a lot of data quickly through the Bluetooth interface, and after a variable amount of data sent, transfer fails with error:
     kernel: [  415.247453] Bluetooth: hci0 hardware error 0x00
Found on T100TA.
After reverting this commit, send works fine for any file size.
Signed-off-by Frederic Danis <[email protected]>
---
v2: Re-send to correct people

Quoted 6 lines

Quoted 2 lines
  drivers/tty/serial/8250/8250_dma.c | 4 ----
  1 file changed, 4 deletions(-)
Andy, any objections?
Frederic, don't you want to see this backported to 4.0 and newer?

Yes, you're right, unless Andy has any objection this should be good

Regards

Fred

Frederic Danis

author

2015-10-09 14:45 UTC #3 lore raw

Hello Greg,

Quoted 6 lines · Frederic Danis

Quoted 4 lines
Andy, any objections?
Frederic, don't you want to see this backported to 4.0 and newer?
Yes, you're right, unless Andy has any objection this should be good

This is first time for me that patch may be applied to previous kernel.

Is there something specific I should do to allow this patch to be applied and backported to 4.0 and newer ?

Regards

Fred

Signature · 2 lines

Frederic Danis                            Open Source Technology Center
[email protected]                              Intel Corporation

Andy Shevchenko

2015-10-09 14:48 UTC #4 lore raw

Quoted 8 lines · Frederic Danis

Hello Greg,
Quoted 5 lines · Frederic Danis
Quoted 4 lines
Andy, any objections?
Frederic, don't you want to see this backported to 4.0 and newer?

Quoted 8 lines

Quoted 2 lines
Yes, you're right, unless Andy has any objection this should be good
This is first time for me that patch may be applied to previous kernel.
Is there something specific I should do to allow this patch to be applied and backported to 4.0 and newer ?

Earlier we use to Cc: [email protected]
(I don't know if it's still a case)

Now the tag Fixes: is in use, like you may add the following line to th e commit message:

Fixes 9119fba0cfed (serial: 8250_dma: don't bother DMA with small

transfers)

Signature · 2 lines

Andy Shevchenko <[email protected]>
Intel Finland Oy

Fabio Estevam

2015-10-09 15:09 UTC #5 lore raw

In reply to Frederic Danis

Quoted 4 lines · Frederic Danis

This is first time for me that patch may be applied to previous kernel.
Is there something specific I should do to allow this patch to be applied and backported to 4.0 and newer ?

You can find the instructions at Documentation/stable_kernel_rules.txt

Andy Shevchenko

2015-10-06 14:39 UTC #6 lore raw

In reply to Greg KH

Quoted 13 lines · Greg KH

Quoted 12 lines · Frederic Danis
This reverts commit 9119fba0cfeda6d415c9f068df66838a104b87cb.
This commit prevents from sending "big" file using Bluetooth. When sending a lot of data quickly through the Bluetooth interface, and
after a variable amount of data sent, transfer fails with error:
    kernel: [  415.247453] Bluetooth: hci0 hardware error 0x00
Found on T100TA.
After reverting this commit, send works fine for any file size.

Quoted 8 lines

Quoted 6 lines
Signed-off-by Frederic Danis <[email protected]>
---
v2: Re-send to correct people
 drivers/tty/serial/8250/8250_dma.c | 4 ----
 1 file changed, 4 deletions(-)
Andy, any objections?

No.

P.S. Unfortunately it's not easy to reproduce on our side, so I trust Frederic on this.

Quoted 6 lines

Frederic, don't you want to see this backported to 4.0 and newer?
thanks,
greg k-h

Signature · 2 lines

Andy Shevchenko <[email protected]>
Intel Finland Oy