On Mon, Dec 20, 2021 at 04:59:13PM +0100, Greg Kroah-Hartman wrote:

On Mon, Oct 11, 2021 at 09:02:58PM +0800, Yinbo Zhu wrote:

quoted

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 and S4 (suspend to memory/suspend
to disk) press test procedure, it may happen that the start of
frame was launched in other usb states and cause ohci works failed,
that the phenomenon was hc will allways reproduce the SoF interrupt
and consider that hc doesn't deal with the ed/td/done list in non-
UsbOperational, and 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 so that it can fix ohci SoF abnormally interrupt.

I do not understand this change.  What commit is this fixing?  What
devices today do not work with the code as-is?

quoted

Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
---
Change in v4:
		Rework the commit log information.
		Remove the extra unnecessary blank line. 


 drivers/usb/host/ohci-hcd.c | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index 1f5e693..4fd59fa 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c

@@ -879,7 +879,7 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
 {
 	struct ohci_hcd		*ohci = hcd_to_ohci (hcd);
 	struct ohci_regs __iomem *regs = ohci->regs;
-	int			ints;
+	int			ints, ctl;

New line for a new variable please.

quoted

 
 	/* Read interrupt status (and flush pending writes).  We ignore the
 	 * optimization of checking the LSB of hcca->done_head; it doesn't

@@ -969,9 +969,14 @@ static irqreturn_t ohci_irq (struct usb_hcd *hcd)
 	 * when there's still unlinking to be done (next frame).
 	 */
 	ohci_work(ohci);
-	if ((ints & OHCI_INTR_SF) != 0 && !ohci->ed_rm_list
-			&& ohci->rh_state == OHCI_RH_RUNNING)
+
+	ctl = ohci_readl(ohci, &regs->control);
+	if (((ints & OHCI_INTR_SF) != 0 && !ohci->ed_rm_list
+			&& ohci->rh_state == OHCI_RH_RUNNING) ||
+			((ctl & OHCI_CTRL_HCFS) != OHCI_USB_OPER)) {
 		ohci_writel (ohci, OHCI_INTR_SF, &regs->intrdisable);
+		(void)ohci_readl(ohci, &regs->intrdisable);

No need for (void).

Greg:

I didn't reply to v4 of this patch because the OP never responded to my 
request regarding v3.  See

https://lore.kernel.org/linux-usb/20211011161732.GA822456@rowland.harvard.edu/ (local)

Alan Stern