From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Subject: Re: [PATCH/RFC] net: phy: device: Don't deassert the reset when register and probe Date: Tue, 27 Nov 2018 22:02:41 +0100 Message-ID: References: <1543320947-32763-1-git-send-email-yoshihiro.shimoda.uh@renesas.com> <20181127164411.GB19601@lunn.ch> <4aa356d3-7c99-a9d6-0e6c-d46be7e44948@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Return-path: In-Reply-To: <4aa356d3-7c99-a9d6-0e6c-d46be7e44948@gmail.com> Sender: netdev-owner@vger.kernel.org To: Heiner Kallweit Cc: Andrew Lunn , Yoshihiro Shimoda , Florian Fainelli , "David S. Miller" , netdev , Linux-Renesas , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" List-Id: devicetree@vger.kernel.org Hi Heiner, On Tue, Nov 27, 2018 at 8:47 PM Heiner Kallweit wrote: > On 27.11.2018 17:44, Andrew Lunn wrote: > > On Tue, Nov 27, 2018 at 12:18:20PM +0000, Yoshihiro Shimoda wrote: > >> Some PHY device needs edge signal of the reset, but the previous code > >> is impossible to achieve it like following: > >> > >> 1) Kernel boots by using initramfs. > >> --> No open the nic, so the provious code deasserts the reset by > >> phy_device_register() and phy_probe(). > >> 2) Kernel enters the suspend. > >> --> So, keep the reset signal as deassert. > >> --> On R-Car Salvator-XS board, unfortunately, the board power is > >> turned off. > >> 3) Kernel returns from suspend. > >> 4) ifconfig eth0 up > >> --> Then, since edge signal of the reset doesn't happen, > >> it cannot link up. > > > > Hi Yoshihiro > > > > It sounds like you should be adding code to the suspend/resume > > handling of phylib, so that it toggle the reset on resume. You cannot > > just delete code like you proposed, it is going to break devices. But > > adding code should be O.K. > > > The commit message mentions that the patch is supposed to fix some > issue on the Salvator-XS board. I found the following from a year ago > https://www.spinics.net/lists/netdev/msg457308.html > which is also about PHY reset and this board. Is there still something > open? But as Andrew mentioned already: Just deleting code w/o > checking what it's good for and whether this could have side effects, > isn't a solution. Especially because the patch would silently remove > the call to phy_scan_fixups(). That's correct: my original motivation for picking up Sergei's patches was to make Ethernet work after suspend/resume on the same Salvator-XS board. The main difference seems to be that I was using NFS root, while Shimoda-san is using an initramfs. Hence there probably is an inconsistency in reset handling for an active vs. inactive Ethernet interface. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds