在 2021/10/11 下午1:10, zhuyinbo 写道:
在 2021/10/10 上午3:39, Alan Stern 写道:
On Sat, Oct 09, 2021 at 10:01:25AM +0800, zhuyinbo wrote:
在 2021/10/8 下午10:26, Alan Stern 写道:
On Fri, Oct 08, 2021 at 03:26:10PM +0800, Yinbo Zhu wrote:
The usb states of ohci controller include UsbOperational, UsbReset,
UsbSuspend and UsbResume. Among them, only the UsbOperational state
supports launching the start of frame for host controller according
the ohci protocol spec, but in S3/S4 press test procedure, it may
Nobody reading this will know what "S3/S4 press test procedure" means.
You have to explain it, or use a different name that people will
understand.
okay, I got it.
happen that the start of frame was launched in other usb states and
cause ohci works abnormally then kernel will allways report rcu
call trace. This patch was to add check for host controller
functional states and if it is not UsbOperational state that need
set INTR_SF in intrdisable register to ensure SOF Token generation
was been disabled.
This doesn't make sense. You already mentioned that only the
UsbOperational state supports sending start-of-frame packets. So
if the
controller is in a different state then it won't send these packets,
whether INTR_SF is enabled or not.
What problem are you really trying to solve?
Only UsbOperational state supports sending start-of-frame packets,
but in
fact, in S3/S4 press test procedure,
usb in non-UsbOperational state that send start-of-frame packets but hc
driver doesn't deal with this frame. and hc will
allways lauched the SOF for finishing the frame, the cpu will hand
this sof
interrupt and doesn't deal with time interrupt
that will cause rcu call trace then system doesn't suspend to
memory/disk.
I still don't understand.
Are you saying that your OHCI controller behaves badly because it sends
SOF packets even when the state is different from UsbOperational?
HC will allways report the SoF interrupt in the all time when HC was
not in NO-UsbOperation state.
and no WritebackDoneHead interrupt that is the issue phenomenon. and
this situation is badly state for ohci.
Hi Alan Stern,
even though ed_rm_list is non-NULL, if hc in non-UsbOperation
state set
SoF status in usbsts register that is illegal,
at this time hcd doesn't need care URB whether finished, because hc had
into a wrong state. even thoug it doesn't has this patch,
URB was not be able to finish when hc in above worng state. except
software
can intervence this wrong state. but the SoF bit of usbsts
register was set by HC, and this action will happen always !!! software
clear SoF state I think it isn't make sense. software only disable SoF
interrupt to fix HC wrong state.
This problem happens when you go into S3 or S4 suspend, right? So you
should fix the problem by disabling INTR_SF when the root hub is
suspended. Try adding
/* All ED unlinks should be finished, no need for SOF interrupts */
ohci_writel(ohci, OHCI_INTR_SF, &ohci->regs->intrdisable);
into ohci_rh_suspend(), just before the update_done_list() call. If you
add this then INTR_SF will not be enabled during S3 or S4 suspend, so
the problem shouldn't occur. Does that work for you?
The system doesn't suspend to disk completely by my test result and hc
will always produce SoF interrupt.
I encountered SoF interrupt issue when HC in UsbSuspend state. and I
think when hc in
UsbResume/UsbRest/ SoF interrupt issue may be happen so I disable
INTR_SF in ohci_irq.
So I think disable INTR_SF in suspend function which this way isn't
good for me.
In addition, I hope my patch was not only fix the bug i
encountered and it can limit HC into badly state and it should be the
base limit condition and prevent more unknown problems. In fact, HC
doesn't deal with ed/td list and done list by the ohci spec, so
I think my patch has no risk for ohci.
by the way, root hub state isn't completely same with HC, but
the root hub reset and resume signaling are controlled by the hcfs bits.
and hcd can set hcfs to decide hc usb state, so I judge whether set
SF_INT to interrupt disable register only depend on HC state.
And I have a test, ohci_rh_suspend was called that HC state as gerneral
was also UsbOperational state whatever do s3/s4 test or power on to boot
kernel.
but HCD record it as suspend state on root hub at this time.
In additon, when kernel include my patch, that it does't
happen about
what you descriped that driver will not be able to finish unlinging
URBs.
Because above issue happen in S3/S4(Suspend to disk/Suspend to mem)
test
procedure, if ed_rm_lis is no-NULL but my patch disable SoF interrupt.
then when S3/S4 recovery to cpu idle state that usb resume will be
called,
reume function has following logic, URB will continue to be processed.
static int ohci_rh_resume (struct ohci_hcd *ohci)
{
...
242 if (ohci->ed_rm_list)
243 ohci_writel (ohci, OHCI_INTR_SF,
&ohci->regs->intrenable);
...
}
I'm worried that your patch may disable INTR_SF even when the controller
has not gone into S3 or S4 suspend. Maybe this won't cause problems,
but it's better to be safe and do the disable _only_ when a suspend
occurs.
Alan Stern
Hi Alan Stern,
According to the previous statement, I think my patch has no risk
on ohci.
