On Thu, Feb 1, 2018 at 11:35 AM, <Mario.Limonciello@xxxxxxxx> wrote: > > >> -----Original Message----- >> From: Dmitry Torokhov [mailto:dmitry.torokhov@xxxxxxxxx] >> Sent: Thursday, February 1, 2018 1:30 PM >> To: Pali Rohár <pali.rohar@xxxxxxxxx> >> Cc: Limonciello, Mario <Mario_Limonciello@xxxxxxxx>; linux- >> input@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx >> Subject: Re: Dell docking station & Dell Embedded Controller & PS/2 devices >> >> Hi Pali, >> >> On Wed, Jan 24, 2018 at 11:41:21AM +0100, Pali Rohár wrote: >> > Hi Dmitry! >> > >> > I'm observing a problem with internal touchpad (handled by psmouse.ko) >> > on Dell laptops connected to Dell E docking station. When I connect >> > external PS/2 keyboard to docking station then internal laptop touchpad >> > switch from multitouch absolute mode to relative bare PS/2 mode. >> > >> > And because ALPS driver in psmouse.ko is capable to process interleaved >> > bare 3-byte PS/2 packets with 6-byte ALPS packets (which handles >> > trackstick data on some ALPS models), ALPS driver does not show any >> > message about this "downgrade" from multitouch to bare mode. And >> > continue working in bare mode. >> > >> > When I rmmod psmouse and modprobe it again, then touchpad switch back to >> > multitouch mode. >> > >> > Mario told me that Dell Embedded Controller, which handle internal >> > keyboard, internal touchpad and external PS/2 keyboard, automatically >> > send RESET command to *all* those devices when external PS/2 keyboard is >> > connected. Therefore this is reason why touchpad downgrade to to bare >> > mode. And according to Mario, host system should issue vendor specific >> > PS/2 commands to re-initialize all PS/2 devices when this situation >> > happen. Mario also told me that Windows is doing this action. >> >> Yeah, I remember fun with Inspiron 8100 - when you dock it it woudl >> silently switch Synaptics touchpad into standard mode and it would not >> come back as Synaptics until you disconnect. And there was no >> notification to the kernel as far as I could tell. >> >> It could be that we need to monitor dock events and then kick reconnect >> of serio port, either from userspace via udev (I think that would be >> preferred), or in kernel. >> >> > >> > Every time when I connect external PS/2 keyboard to dock I see this >> > message in dmesg: >> > >> > Spurious ACK... Some program might be trying to access hardware directly. >> > >> > I see it also every time when I dock laptop into docking station (to >> > which is keyboard already connected). And it happens also when I connect >> > external PS/2 mouse to dock. >> > >> > Dmitry, how to handle this situation to re-initialize psmouse.ko when >> > external PS/2 device is connected to Dell E docking station? According >> > to Mario, this is how Dell Embedded Controller is designed and suppose >> > how OS should work with it. >> > >> > Manually rmmoding and modprobing for every docking/undocking laptop is >> > not ideal solution. >> > >> > Could it be possible to use that Spurious ATKBD_RET_ACK from atkbd.c be >> > handled on Dell systems (probably via DMI) as an event to reset and >> > reinitialize all PS/2 devices? >> >> So we need to figure out what exactly we are getting from the docking >> station in this case. We do try to handle the new device 0xaa 0x00 >> announcements: > > Docking station itself won't have sent any events. The PS2 ports in it > are electrically wired to the external PS2 pins in the docking adapter on > the system. > > System EC is what will be sending any PS2 events. OK, it does not matter from the input layer POW, if they are PS/2 events they should be coming from i8042. > >> >> /* Check if this is a new device announcement (0xAA 0x00) */ >> if (unlikely(psmouse->packet[0] == PSMOUSE_RET_BAT && psmouse- >> >pktcnt <= 2)) { >> if (psmouse->pktcnt == 1) { >> psmouse->last = jiffies; >> goto out; >> } >> >> if (psmouse->packet[1] == PSMOUSE_RET_ID || >> (psmouse->protocol->type == PSMOUSE_HGPK && >> psmouse->packet[1] == PSMOUSE_RET_BAT)) { >> __psmouse_set_state(psmouse, PSMOUSE_IGNORE); >> serio_reconnect(serio); >> goto out; >> } >> >> ... >> >> I am not sure where the "spurious ACK comes from". Can you enable i8042 >> debug before trying to dock and capture the data stream from the mouse? >> > > The system EC has reset PS2 devices (but AFAIK kernel won't have seen this > communication). So what kind of communication does EC send when docking? It sounds it is completely out of band from PS/2 connection. Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
