On 19 November 2015 at 21:45, Douglas Anderson <dianders@xxxxxxxxxxxx> wrote: > In general it is wise to clear interrupts before processing them. If > you don't do that, you can get: > 1. Interrupt happens > 2. You look at system state and process interrupt > 3. A new interrupt happens > 4. You clear interrupt without processing it. > > This patch was actually a first attempt to fix missing device insertions > as described in (usb: dwc2: host: Fix missing device insertions) and it > did solve some of the signal bouncing problems but not all of > them (which is why I submitted the other patch). Specifically, this > patch itself would sometimes change: > 1. hardware sees connect > 2. hardware sees disconnect > 3. hardware sees connect > 4. dwc2_port_intr() - clears connect interrupt > 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() > > ...to: > 1. hardware sees connect > 2. hardware sees disconnect > 3. dwc2_port_intr() - clears connect interrupt > 4. hardware sees connect > 5. dwc2_handle_common_intr() - calls dwc2_hcd_disconnect() > > ...but with different timing then sometimes we'd still miss cable > insertions. > > In any case, though this patch doesn't fix any (known) problems, it > still seems wise as a general policy to clear interrupt before handling > them. > > Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx> > Acked-by: John Youn <johnyoun@xxxxxxxxxxxx> > Tested-by: John Youn <johnyoun@xxxxxxxxxxxx> > --- > Changes in v3: > - Don't (uselessly) clear the PRTINT anymore (Felipe Balbi). > > Changes in v2: None > Hi. It seems that towards the end of hcd_intr.c you seem to be switching a few calls of dwc2_writel() to plain writel(). It looks like something that is easily overlooked but please always use dwc2_writel to preserve correct register endianness on big-endian platforms. Br, -- Antti -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
