On 1/30/26 9:13 PM, Jonas Karlman wrote:
Hello Jonas,
Is this a USB controller related problem/limitation ? Maybe the DWC2
driver needs fixing instead, to handler larger buffers ?
I accidentally mixed up what host controller was being used, the board in
question is using a generic-echi controller not the DWC2 as I stated.
I dove deeper
Thank you for doing that.
and it looks like there could be an issue with ehci-hcd
and handling of short packets, see below debug print that dumps the qTD
and where it can be seen that the first packet is short and using the
xfr_bytes - totalbytes of the first qTD with a short packet fixes my
issue.
BOOTP broadcast 4
** asix_send_common(), len 342
ehci_submit_bulk_msg: dev='usb@ff100000', udev=00000000f9f2d520
dev=00000000f9f2d520, pipe=c0018303, buffer=00000000f9ee13c0, length=350,
req=0000000000000000
QH: next=0x1, alt=0x11, token=0x8c00, totalbytes=0, xfr_bytes=0
qTD[0]: next=0x1, alt=0x1, token=0x8c00, totalbytes=0, xfr_bytes=350
TOKEN=0x8c00
Tx: len = 346, actual = 350, err = 0
ax88179_eth_recv: first try, len=0
ehci_submit_bulk_msg: dev='usb@ff100000', udev=00000000f9f2d520
dev=00000000f9f2d520, pipe=c0010383, buffer=00000000f9f2df00, length=26624,
req=0000000000000000
QH: next=0x1, alt=0x11, token=0xa7808d00, totalbytes=10112
qTD[0]: next=0xf9f2a140, alt=0x1, token=0xbe989d00, totalbytes=16024,
xfr_bytes=16384 <<-- SHORT
qTD[1]: next=0x1, alt=0x1, token=0xa7808d00, totalbytes=10112, xfr_bytes=10240
<<-- SHORT
TOKEN=0xa7808d00
ax88179_eth_recv: second try, len=16512
ax88179_eth_recv: 2 packets received, pkt header at 112
ax88179_eth_recv: return packet of 0 bytes (1 packets left)
ax88179_eth_recv: return packet of 0 bytes (0 packets left)
ax88179_eth_recv: first try, len=0
ehci_submit_bulk_msg: dev='usb@ff100000', udev=00000000f9f2d520
dev=00000000f9f2d520, pipe=c0010383, buffer=00000000f9f2df00, length=26624,
req=0000000000000000
QH: next=0x1, alt=0x11, token=0x27a08d00, totalbytes=10144
qTD[0]: next=0xf9f2a140, alt=0x1, token=0x3e889d00, totalbytes=16008,
xfr_bytes=16384 <<-- SHORT
qTD[1]: next=0x1, alt=0x1, token=0x27a08d00, totalbytes=10144, xfr_bytes=10240
<<-- SHORT
TOKEN=0x27a08d00
ax88179_eth_recv: second try, len=16480
ax88179_eth_recv: 2 packets received, pkt header at 80
ax88179_eth_recv: return packet of 5429 bytes (1 packets left)
ax88179_eth_recv: return packet of 4149 bytes (0 packets left)
Could you please share the printing diff ?
Maybe I am missing something, but the transfers above are longer than 20
kiB ? Also, how does the printout look _after_ the change below was
applied ?
The diff below seem to solve my issue even better, aligns the ehci
transfers to only use one qTD with a 20kb buffer for optimal performance.
But that is probably still not a good solution, ehci-hcd should probably
gain proper support for short packet handling and usb_ether_register()
could start using a 4kb aligned rxbuf to make sure 20kb transfers instead
of 16kb transfers are used for ehci controllers.
Maybe I should just drop this patch and address your feedback on
remaining patches for v2?
Maybe at least a subset of these patches can be picked that way, yes.
diff --git a/drivers/usb/eth/asix88179.c b/drivers/usb/eth/asix88179.c
index 69d3073b669a..a04952b5eb74 100644
--- a/drivers/usb/eth/asix88179.c
+++ b/drivers/usb/eth/asix88179.c
@@ -475,7 +475,6 @@ static int asix_init_common(struct ueth_data *dev,
/* RX bulk configuration */
asix_write_cmd(dev, AX_ACCESS_MAC, AX_RX_BULKIN_QCTRL, 5, 5, tmp);
- dev_priv->rx_urb_size = (1024 * (tmp[3] + 2));
if (*tmp16 & GMII_PHY_PHYSR_FULL)
mode |= AX_MEDIUM_FULL_DUPLEX;
asix_write_cmd(dev, AX_ACCESS_MAC, AX_MEDIUM_STATUS_MODE,
diff --git a/drivers/usb/eth/usb_ether.c b/drivers/usb/eth/usb_ether.c
index 8bba3e0974e6..02c93b40dd3e 100644
--- a/drivers/usb/eth/usb_ether.c
+++ b/drivers/usb/eth/usb_ether.c
@@ -72,7 +72,7 @@ int usb_ether_register(struct udevice *dev, struct ueth_data
*ueth, int rxsize)
}
ueth->rxsize = rxsize;
- ueth->rxbuf = memalign(ARCH_DMA_MINALIGN, rxsize);
+ ueth->rxbuf = memalign(4096, rxsize);
What is your current ARCH_DMA_MINALIGN ?
