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Date:   Sun, 29 Nov 2020 13:59:33 -0800
From:   Guenter Roeck <linux@roeck-us.net>
To:     Wilken Gottwalt <wilken.gottwalt@posteo.net>
Cc:     Jonas Malaco <jonas@protocubo.io>, linux-kernel@vger.kernel.org,
        Jean Delvare <jdelvare@suse.com>,
        Jonathan Corbet <corbet@lwn.net>, linux-hwmon@vger.kernel.org
Subject: Re: [PATCH] hwmon: corsair-psu: update supported devices
Message-ID: <20201129215933.GA131003@roeck-us.net>
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On Sun, Nov 29, 2020 at 04:54:43PM +0100, Wilken Gottwalt wrote:
> On Sun, 29 Nov 2020 05:00:49 -0800
> Guenter Roeck <linux@roeck-us.net> wrote:
> 
> > On Sun, Nov 29, 2020 at 07:36:18AM +0100, Wilken Gottwalt wrote:
> > > On Sat, 28 Nov 2020 17:21:40 -0300
> > > Jonas Malaco <jonas@protocubo.io> wrote:
> > > 
> > > > On Sat, Nov 28, 2020 at 7:35 AM Wilken Gottwalt
> > > > <wilken.gottwalt@posteo.net> wrote:
> > > > >
> > > > > On Sat, 28 Nov 2020 02:37:38 -0300
> > > > > Jonas Malaco <jonas@protocubo.io> wrote:
> > > > >
> > > > > > On Thu, Nov 26, 2020 at 8:43 AM Wilken Gottwalt
> > > > > > <wilken.gottwalt@posteo.net> wrote:
> > > > > > >
> > > > > > > Adds support for another Corsair PSUs series: AX760i, AX860i, AX1200i,
> > > > > > > AX1500i and AX1600i. The first 3 power supplies are supported through
> > > > > > > the Corsair Link USB Dongle which is some kind of USB/Serial/TTL
> > > > > > > converter especially made for the COM ports of these power supplies.
> > > > > > > There are 3 known revisions of these adapters. The AX1500i power supply
> > > > > > > has revision 3 built into the case and AX1600i is the only one in that
> > > > > > > series, which has an unique usb hid id like the RM/RX series.
> > > > > >
> > > > > > Can I ask what AXi power supplies were tested?
> > > > > >
> > > > > > I ask because, based on the user-space implementations I am aware of,
> > > > > > the AXi dongle protocol appears to be different from the RMi/HXi series.
> > > > >
> > > > > I was not able to test this against the AX power supplies, they are really
> > > > > hard to find (and are far to expensive). But I went through all these tools
> > > > > and stuck to the most common commands, which all 3 series support. Not every
> > > > > series supports all commands (there also seem to be different firmwares in
> > > > > the micro-conrollers). But this is fine, some sensors will show up as N/A.
> > > > > Even my HX850i does not support all commands covered in this driver.
> > > > 
> > > > I think the similarities come from all using wrappers over the PMBus
> > > > interface to the voltage controller.  But I am not sure the wrapping
> > > > protocols are identical.
> > > > 
> > > > For example, cpsumon shows significantly more things going on during a
> > > > read than what is needed for the RMi/HXi series.[1]
> > > > 
> > > > [1] https://github.com/ka87/cpsumon/blob/fd639684d7f9/libcpsumon/src/cpsumon.c#L213-L231
> > > > 
> > > > 
> > > > >
> > > > > > AXi dongle:
> > > > > >  - https://github.com/ka87/cpsumon
> > > > >
> > > > > This tool made me to consider including the AX series, because it uses some
> > > > > of the same commands on the AX760i, AX860i, AX1200i and AX1500i. But it is
> > > > > a usb-serial tool only. But it was nice to know, that the commands are mostly
> > > > > the same. I left out all the commands for configuring, PCIe power rails,
> > > > > efficiency and others which do not really belong into hwmon.
> > > > >
> > > > > > RMi/HXi:
> > > > > >  - https://github.com/jonasmalacofilho/liquidctl
> > > > > >  - https://github.com/audiohacked/OpenCorsairLink
> > > > >
> > > > > This tool made me include the AX series, because it uses the rmi protocol
> > > > > component for the rmi driver (RM/HX series) and the corsair dongles.
> > > > 
> > > > The corsairlink_driver_dongle has no implementations for reading sensor
> > > > data (compare that with the corsairlink_driver_rmi).[2][3]  There is
> > > > also no code that actually tries to read (write) from (to) the device
> > > > using that dongle driver.[4]
> > > > 
> > > > I also looked at a few of the issues, and all of the ones I read
> > > > mentioned AXi support being under development, and the hypothesis of the
> > > > AXi series being compatible with the RMi/HXi code still remaining to be
> > > > confirmed.
> > > > 
> > > > [2] https://github.com/audiohacked/OpenCorsairLink/blob/61d336a61b85/drivers/dongle.c#L33-L39
> > > > [3] https://github.com/audiohacked/OpenCorsairLink/blob/61d336a61b85/drivers/rmi.c#L33-L57
> > > > [4] https://github.com/audiohacked/OpenCorsairLink/blob/61d336a61b85/main.c#L106
> > > > 
> > > > 
> > > > >
> > > > > >  - https://github.com/notaz/corsairmi
> > > > >
> > > > > This one covers only some HX/RM PSUs, but is uses the rawhid access which
> > > > > made me looking up the actual usb chips/bridges Corsair uses.
> > > > >
> > > > > >
> > > > > > One additional concern is that the non-HID AXi dongles may only have bulk
> > > > > > USB endpoints, and this is a HID driver.[1]
> > > > >
> > > > > You are right, in the case of the dongles it could be different. But I did
> > > > > some research on Corsair usb driven devices and they really like to stick to
> > > > > the cp210x, which is an usb hid bridge. The commit
> > > > > b9326057a3d8447f5d2e74a7b521ccf21add2ec0 actually covers two Corsair USB
> > > > > dongles as a cp210x device. So it is very likely that all Corsair PSUs with
> > > > > such an interface/dongle use usb hid. But I'm completely open to get proven
> > > > > wrong. Actually I really would like to see this tested by people who have
> > > > > access to the more rare devices.
> > > > 
> > > > I could be wrong (and I am sorry for the noise if that is the case), but
> > > > as far as I can see the cp210x does not create a HID device.
> > > 
> > > No no, this is fine. It really helps if some more people are looking into this.
> > > I wish I had access to at least one of the later models (AX1500i/AX1600i), I
> > > make mistakes from time to time. And it really doesn't help that Corsair changes
> > > single devices in the same product line by firmware update. The AX1600i seems to
> > > be the only one, which uses exactly the same protocol like the RM/HX series, but
> > > is missing the actual usb hid part. But there seems to be a firmware where the
> > > usb hid part was available for a short time. So, what to do? Remove the AXi part
> > > completely or keep only the AX1600i?
> > > 
> > > Guenter, what would you suggest?
> > > 
> > I'd suggest to remove it completely, and explain the reason. Anything else will
> > just create trouble with people demanding to know why their power supply is not
> > supported even though it is listed as supported. And, believe me, you don't want
> > to be on the receiving side of those complaints. The Internet is much less
> > friendly nowadays than it used to be.
> 
> So how is the procedure for this? Just revert it and make a common patch out of
> it with a proper explanation?
> 
> And yeah, I know exactly what you mean. I remember very well how the "internet"
> got it first ugly hit in the 90s with the upcoming of Flash ... and then the
> "social media". :D Thanks for your help.
> 

Can I just drop your previous patch and you send me another - more restrictive -
one ?

Thanks,
Guenter

> greetings,
> Wilken
> 
> > Guenter
> > 
> > > > Thanks again,
> > > > Jonas
> > > > 
> > > > 
> > > > >
> > > > > > Thanks,
> > > > > > Jonas
> > > > > >
> > > > > > [1] https://github.com/ka87/cpsumon/issues/4
> > > > >
> > > > > Yes ... that one. The last revision of the dongle could indeed be a problem.
> > > > > But I'm not really sure what is described here. The last commenter is actually
> > > > > the one who provided the cp210x patch mentioned up there. The problem here is,
> > > > > the AX1500i has both connectors, USB and that other one. I call it the other
> > > > > one because it is the only PSU where it is labeled I2C COMM instead of COMM
> > > > > only. But at the same time this tools uses the same commands for this PSU.
> > > > >
> > > > > So, only some real hardware tests will show.
> > > > >
> > > > > Greetings,
> > > > > Wilken
> > > > >
> > > > > > >
> > > > > > > The patch also changes the usb hid ids to use upper case letters to be
> > > > > > > consistent with the rest of the hex numbers in the driver and updates
> > > > > > > the hwmon documentation.
> > > > > > >
> > > > > > > This patch adds:
> > > > > > > - hwmon/corsair-psu documentation update
> > > > > > > - corsair-psu driver update
> > > > > > >
> > > > > > > Signed-off-by: Wilken Gottwalt <wilken.gottwalt@posteo.net>
> > > > > > > ---
> > > > > > >  Documentation/hwmon/corsair-psu.rst | 10 +++++++++
> > > > > > >  drivers/hwmon/Kconfig               |  7 +++---
> > > > > > >  drivers/hwmon/corsair-psu.c         | 33 +++++++++++++++++++----------
> > > > > > >  3 files changed, 36 insertions(+), 14 deletions(-)
> > > > > > >
> > > > > > > diff --git a/Documentation/hwmon/corsair-psu.rst b/Documentation/hwmon/corsair-psu.rst
> > > > > > > index 396b95c9a76a..6227e9046d73 100644
> > > > > > > --- a/Documentation/hwmon/corsair-psu.rst
> > > > > > > +++ b/Documentation/hwmon/corsair-psu.rst
> > > > > > > @@ -7,6 +7,16 @@ Supported devices:
> > > > > > >
> > > > > > >  * Corsair Power Supplies
> > > > > > >
> > > > > > > +  Corsair AX760i (by Corsair Link USB Dongle)
> > > > > > > +
> > > > > > > +  Corsair AX860i (by Corsair Link USB Dongle)
> > > > > > > +
> > > > > > > +  Corsair AX1200i (by Corsair Link USB Dongle)
> > > > > > > +
> > > > > > > +  Corsair AX1500i (by builtin Corsair Link USB Dongle)
> > > > > > > +
> > > > > > > +  Corsair AX1600i
> > > > > > > +
> > > > > > >    Corsair HX550i
> > > > > > >
> > > > > > >    Corsair HX650i
> > > > > > > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> > > > > > > index 716df51edc87..3c059fc23cd6 100644
> > > > > > > --- a/drivers/hwmon/Kconfig
> > > > > > > +++ b/drivers/hwmon/Kconfig
> > > > > > > @@ -453,11 +453,12 @@ config SENSORS_CORSAIR_PSU
> > > > > > >         tristate "Corsair PSU HID controller"
> > > > > > >         depends on HID
> > > > > > >         help
> > > > > > > -         If you say yes here you get support for Corsair PSUs with a HID
> > > > > > > +         If you say yes here you get support for Corsair PSUs with an USB HID
> > > > > > >           interface.
> > > > > > >           Currently this driver supports the (RM/HX)550i, (RM/HX)650i,
> > > > > > > -         (RM/HX)750i, (RM/HX)850i, (RM/HX)1000i and HX1200i power supplies
> > > > > > > -         by Corsair.
> > > > > > > +         (RM/HX)750i, (RM/HX)850i, (RM/HX)1000i, HX1200i and AX1600i power
> > > > > > > +         supplies by Corsair. The AX760i, AX860i, AX1200i and AX1500i
> > > > > > > +         power supplies are supported through the Corsair Link USB Dongle.
> > > > > > >
> > > > > > >           This driver can also be built as a module. If so, the module
> > > > > > >           will be called corsair-psu.
> > > > > > > diff --git a/drivers/hwmon/corsair-psu.c b/drivers/hwmon/corsair-psu.c
> > > > > > > index 99494056f4bd..0146dda3e2c3 100644
> > > > > > > --- a/drivers/hwmon/corsair-psu.c
> > > > > > > +++ b/drivers/hwmon/corsair-psu.c
> > > > > > > @@ -571,17 +571,28 @@ static int corsairpsu_raw_event(struct hid_device *hdev, struct
> > > > > > > hid_report *repo }
> > > > > > >
> > > > > > >  static const struct hid_device_id corsairpsu_idtable[] = {
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c03) }, /* Corsair HX550i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c04) }, /* Corsair HX650i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c05) }, /* Corsair HX750i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c06) }, /* Corsair HX850i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c07) }, /* Corsair HX1000i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c08) }, /* Corsair HX1200i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c09) }, /* Corsair RM550i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c0a) }, /* Corsair RM650i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c0b) }, /* Corsair RM750i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c0c) }, /* Corsair RM850i */
> > > > > > > -       { HID_USB_DEVICE(0x1b1c, 0x1c0d) }, /* Corsair RM1000i */
> > > > > > > +       /*
> > > > > > > +        * The Corsair USB/COM Dongles appear in at least 3 different revisions, where
> > > > > > > rev 1 and 2
> > > > > > > +        * are commonly used with the AX760i, AX860i and AX1200i, while rev3 is rarely
> > > > > > > seen with
> > > > > > > +        * these PSUs. Rev3 is also build into the AX1500i, while the AX1600i is the
> > > > > > > first PSU of
> > > > > > > +        * this series which has an unique usb hid id. Though, the actual device name is
> > > > > > > part of
> > > > > > > +        * the HID message protocol, so it doesn't matter which dongle is connected.
> > > > > > > +        */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C00) }, /* Corsair Link USB/COM Dongle rev1 */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C01) }, /* Corsair Link USB/COM Dongle rev2 */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C02) }, /* Corsair Link USB/COM Dongle rev3
> > > > > > > (AX1500i) */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C03) }, /* Corsair HX550i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C04) }, /* Corsair HX650i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C05) }, /* Corsair HX750i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C06) }, /* Corsair HX850i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C07) }, /* Corsair HX1000i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C08) }, /* Corsair HX1200i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C09) }, /* Corsair RM550i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C0A) }, /* Corsair RM650i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C0B) }, /* Corsair RM750i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C0C) }, /* Corsair RM850i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C0D) }, /* Corsair RM1000i */
> > > > > > > +       { HID_USB_DEVICE(0x1B1C, 0x1C11) }, /* Corsair AX1600i */
> > > > > > >         { },
> > > > > > >  };
> > > > > > >  MODULE_DEVICE_TABLE(hid, corsairpsu_idtable);
> > > > > > > --
> > > > > > > 2.29.2
> > > > > > >
> > > > >
> > > 
>