On 12/6/2012 1:06 PM, Igor Grinberg wrote:
On 12/06/12 08:58, Vipin Kumar wrote:
On 12/6/2012 12:17 PM, Igor Grinberg wrote:
On 12/06/12 08:30, Vipin Kumar wrote:
Few pen drives take longer than usual for enumeration. The u-boot unlike linux
does not depend on interrupts and works in polling and timeout mode.
This patch increases this timeout to increase the set of usb sticks that can be
enumerated by u-boot
Signed-off-by: Vipin Kumar<vipin.ku...@st.com>
---
common/usb_hub.c | 27 ++++++++++++++++++++++-----
1 file changed, 22 insertions(+), 5 deletions(-)
diff --git a/common/usb_hub.c b/common/usb_hub.c
index e4a1201..24de9b7 100644
--- a/common/usb_hub.c
+++ b/common/usb_hub.c
@@ -393,17 +393,34 @@ static int usb_hub_configure(struct usb_device *dev)
"" : "no ");
usb_hub_power_on(hub);
+ mdelay(1500);
a 1.5 seconds? This looks like a huge overkill...
Even for broken usb sticks...
Yes, but we are not talking about performance in u-boot. And since we are
working in a polling mode, we only have 1 chance to detect the pen-drive
Of course we _do care_ about performance and 1.5 seconds is huge and not
justified impact.
OK
Where is this value come from? Any real justification? Or just: lets make it
huge...
A bit of both. In routine usb_hub_power_on, we wait for max(pgood_delay,
100) ms
for power to be stable. The pgood_delay can go max upto 512. This is
because max u8 can carry is 255 and pgood_delay is usb_hub_power_on * 2
A few pens request the maximum possible delay and are not stable even
after this. The new added delay is for power to be stable but I agree
that this value is more experimental and I do not have a real written
justification
Also, as I understand from your commit message, this is needed only for broken
pens...
Yes
Why should all others suffer?
If this is really needed, I think you can do better then this.
For example instead of waiting 1.5 seconds no meter what each time,
make it a busy/wait loop (like you do below) and expire after a timeout.
The problem is that I do not know what to wait on in that case. Can you
point me to something
Regards
Vipin
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
http://lists.denx.de/mailman/listinfo/u-boot
