From mboxrd@z Thu Jan 1 00:00:00 1970 From: Przemo Firszt Subject: Re: [PATCH v2 00/10] Input - wacom: conversion to HID driver, series 2 Date: Fri, 25 Jul 2014 20:26:16 +0100 Message-ID: <1406316376.12682.18.camel@fedora-lan> References: <1406225645-32141-1-git-send-email-benjamin.tissoires@redhat.com> <1406292140.2664.17.camel@fedora-lan> <20140725125820.GA12268@mail.corp.redhat.com> <1406295035.2664.43.camel@fedora-lan> <20140725145400.GB12268@mail.corp.redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from aso-006-i450.relay.mailchannels.net ([23.91.64.131]:10451 "EHLO relay.mailchannels.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1760793AbaGYT0Y convert rfc822-to-8bit (ORCPT ); Fri, 25 Jul 2014 15:26:24 -0400 In-Reply-To: <20140725145400.GB12268@mail.corp.redhat.com> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Benjamin Tissoires Cc: Dmitry Torokhov , Jiri Kosina , Ping Cheng , Jason Gerecke , linux-kernel@vger.kernel.org, linux-input@vger.kernel.org Dnia 2014-07-25, pi=C4=85 o godzinie 10:54 -0400, Benjamin Tissoires pi= sze: > [..] Hi Benjamin, > =20 > > If I understand you correctly we cannot have the same entry point i= n > > sysfs for OLEDs unless we can tell userspace somehow if the tablet = is > > conected over USB or over bluetooth. The hardware of Intuos4 Wirele= ss > > over bluetooth allows only 1-bit images. The same hardware over USB > > allows 4-bit images. Formatting of the images is also completely >=20 > Holy crap! I missed that. I did not noticed the 1-bit vs 4-bits > difference :( >=20 > > different and it's not "plain". Check [1] for usb and exisitng > > hid-wacom.c/wacom_scramble function for bluetooth. >=20 > Maybe I overlooked it, but I thought that in case of USB, the scrambl= ing > is done in user space, and in case of BT, the same scrambling made in= the > kernel. They looks very similar so I thought the user-space scramble = for > USB would have fit. However, the 4-bits/1-bits kills that assumption. You're correct - USB requires scrambling in the user space, but scrambling for USB is different than for BT. Example of USB scramble is here: https://github.com/PrzemoF/i4oled/blob/master/src/i4oled.c#L401 > >=20 > > If we want to make it consistent single entry on kernel level we > > probably have to implement image conversion in the kernel. The user= land > > would always use 4-bit, plain formatted images and kernel driver wo= uld > > convert them to 4-bit, wacom usb format or 1-bit wacom bluetooth fo= rmat > > depending on how the tablet is connected. > >=20 > > The downside of this approach is that the user land wouldn't have 1= 00% > > control over 1-bit images for bluetooth as kernel would have to cre= ate > > them from 4-bit images. >=20 > The USB interface is *very* simple: > - if incoming data !=3D 1024 -> reject > - forward everything to the device without in kernel treatment* >=20 > How about just changing the expected size to 256 in case of a BT tabl= et, > and let the user-space scramble in both cases and forward proper raw > data? >=20 > This way, user space will still have control over 1-bit vs 4-bits, an= d > the changes required in the kernel will be small enough. Sounds good to me. Bit more coding in gnome, but it's a small thing. > My concern is that I'd like to have this series in 3.17 and I will no= t > have access to the hardware until next week :/ > Having all of the user-spaces breakages in the same kernel release wi= ll > I think simplify the user space work. I agree. P.S. Could you send me that set of 23 patches using git-send-email that I should apply on top of linux-next? I got it from lkml, but there is still something messed (fails on patch 09/23). Of course, if it's not a problem for you :-) --=20 Kind regards, Przemo Firszt -- To unsubscribe from this list: send the line "unsubscribe linux-input" = in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html