From: Andy Shevchenko <email@example.com> To: Jack Pham <firstname.lastname@example.org> Cc: Thinh Nguyen <Thinh.Nguyen@synopsys.com>, John Stultz <email@example.com>, Amit Pundir <firstname.lastname@example.org>, Ray Chi <email@example.com>, Ferry Toth <firstname.lastname@example.org>, Chunfeng Yun <email@example.com>, Marek Szyprowski <firstname.lastname@example.org>, Li Jun <email@example.com>, Felipe Balbi <firstname.lastname@example.org>, Greg Kroah-Hartman <email@example.com>, firstname.lastname@example.org, Wesley Cheng <email@example.com> Subject: Re: [RFT][PATCH] usb: dwc3: Decouple USB 2.0 L1 & L2 events Date: Wed, 18 Aug 2021 12:33:23 +0300 [thread overview] Message-ID: <YRzT4y87Nt8ICFJfirstname.lastname@example.org> (raw) In-Reply-To: <20210818012859.GB30805@jackp-linux.qualcomm.com> On Tue, Aug 17, 2021 at 06:28:59PM -0700, Jack Pham wrote: > On Thu, Aug 12, 2021 at 01:26:35AM -0700, Jack Pham wrote: > > On DWC_usb3 revisions 3.00a and newer (including DWC_usb31 and > > DWC_usb32) the GUCTL1 register gained the DEV_DECOUPLE_L1L2_EVT > > field (bit 31) which when enabled allows the controller in device > > mode to treat USB 2.0 L1 LPM & L2 events separately. > > > > After commit d1d90dd27254 ("usb: dwc3: gadget: Enable suspend > > events") the controller will now receive events (and therefore > > interrupts) for every state change when entering/exiting either > > L1 or L2 states. Since L1 is handled entirely by the hardware > > and requires no software intervention, there is no need to even > > enable these events and unnecessarily notify the gadget driver. > > Enable the aforementioned bit to help reduce the overall interrupt > > count for these L1 events that don't need to be handled while > > retaining the events for full L2 suspend/wakeup. > > Hi folks in To: > > I'd like to request if any of you could help test this patch on your > boards to help make sure it doesn't cause any regressions since I know > some of the recent dwc3 patches from Qualcomm have been found to break > other devices :(. So I'm hoping to avoid that even for a patch as > small as this. > > Hoping this could be tried out on boards/SoCs such as db845c, hikey960, > Exynos, the Intel "lakes", etc. Ideally this needs validation with a > high-speed connection to a USB 3.x host, which increases the chances > that USB 2.0 Link Power Management is supported. > > The overall goal of this patch is to eliminate events generated for > L1 entry/exit, so we should see a slight reduction in interrupt counts > when checking `grep dwc3 /proc/interrupts` for comparable traffic. Unfortunately I'm quite busy lately with more important stuff and I dunno if I will be able to test this in reasonable time. So, if Ferry volunteers, then we can cover Intel Merrifield platform as well. -- With Best Regards, Andy Shevchenko
next prev parent reply other threads:[~2021-08-18 9:35 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-08-12 8:26 [PATCH] " Jack Pham 2021-08-18 1:28 ` [RFT][PATCH] " Jack Pham 2021-08-18 2:07 ` John Stultz 2021-08-18 7:52 ` Jun Li 2021-08-18 9:09 ` Amit Pundir 2021-08-18 9:33 ` Andy Shevchenko [this message] 2021-08-18 19:48 ` Ferry Toth 2021-08-19 12:26 ` Andy Shevchenko 2021-08-20 12:17 ` Jack Pham 2021-08-19 2:01 ` Thinh Nguyen 2021-08-18 5:08 ` [PATCH] " Felipe Balbi
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