From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from wp530.webpack.hosteurope.de (wp530.webpack.hosteurope.de [80.237.130.52]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DA3CC1846 for ; Fri, 6 Jan 2023 12:05:38 +0000 (UTC) Received: from [2a02:8108:963f:de38:eca4:7d19:f9a2:22c5]; authenticated by wp530.webpack.hosteurope.de running ExIM with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) id 1pDlTc-0001Yv-13; Fri, 06 Jan 2023 13:05:36 +0100 Message-ID: Date: Fri, 6 Jan 2023 13:05:35 +0100 Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.6.0 Subject: Re: commit 3497b9a5 (usb: dwc3: add power down scale setting) breaks imx8mp Content-Language: en-US, de-DE To: Rasmus Villemoes , Greg Kroah-Hartman , Li Jun Cc: LKML , "regressions@lists.linux.dev" References: <5ae757aa-5b0e-be81-e87c-134e2ba5205d@prevas.dk> From: "Linux kernel regression tracking (#adding)" Reply-To: Thorsten Leemhuis In-Reply-To: <5ae757aa-5b0e-be81-e87c-134e2ba5205d@prevas.dk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-bounce-key: webpack.hosteurope.de;regressions@leemhuis.info;1673006738;ce4c7929; X-HE-SMSGID: 1pDlTc-0001Yv-13 [CCing the regression list, as it should be in the loop for regressions: https://docs.kernel.org/admin-guide/reporting-regressions.html] [TLDR: I'm adding this report to the list of tracked Linux kernel regressions; all text you find below is based on a few templates paragraphs you might have encountered already already in similar form. See link in footer if these mails annoy you.] On 06.01.23 12:54, Rasmus Villemoes wrote: > We have an imx8mp board with a lan7801 usb ethernet chip hardwired on > the PCB, which is used as the host port for a Microchip KSZ9567 switch. > > While trying to update the kernel to 6.1.y, I found something quite > weird: When the switch was being probed for the second time (the first > ends with a standard -EPROBE_DEFER), the board would spontaneously reset. > > Now when I disable the switch driver in .config just to see how far I > could otherwise get, the lan7801 device didn't appear until about 47 > seconds after boot. Bisecting unambiguously points at 3497b9a5, and > digging in, it's pretty obvious why that is bogus at least for imx8mp. > > The .dtsi file lists IMX8MP_CLK_USB_ROOT as the "suspend" clk, and > clk_get_rate() of that returns 500000000 ; divided by 16000 that's > 31250, which certainly doesn't fit in the 13-bit field GCTL_PWRDNSCALE. > But I assume the .dtsi file is wrong, because imx8mq.dtsi has > 74bd5951dd3 (arm64: dts: imx8mq: correct usb controller clocks), and it > seems likely from the commit log of 3497b9a5 that it was at least tested > on imx8mq. > > Now I have no idea if the right clock for imx8mp is also some 32kHz clk, > but it would certainly make sense; unlike what the reference manual > claims, it seems that the reset value of the GCTL register is > 0x00112004, amounting to a pwrdwnscale value of 0x00100000>>19 == 2 == > 32kHz/16kHz, and that could explain why things worked just fine without > 3497b9a5. > > Li Jun, please either revert 3497b9a5 or figure out if imx8mp.dtsi is > broken and needs a fix similar to 74bd5951dd3. Thanks for the report. To be sure the issue doesn't fall through the cracks unnoticed, I'm adding it to regzbot, the Linux kernel regression tracking bot: #regzbot ^introduced 3497b9a5c8c #regzbot title usb: dwc3: imx8mp broken #regzbot ignore-activity This isn't a regression? This issue or a fix for it are already discussed somewhere else? It was fixed already? You want to clarify when the regression started to happen? Or point out I got the title or something else totally wrong? Then just reply and tell me -- ideally while also telling regzbot about it, as explained by the page listed in the footer of this mail. Reminder for developers: When fixing the issue, add 'Link:' tags pointing to the report (see page linked in footer for details). Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat) -- Everything you wanna know about Linux kernel regression tracking: https://linux-regtracking.leemhuis.info/about/#tldr That page also explains what to do if mails like this annoy you.