From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dmitry Torokhov Subject: Re: [PATCH 3/3] goldfish: multitouch: no extra EV_SYN Date: Fri, 26 Feb 2016 11:57:46 -0800 Message-ID: <20160226195746.GA3769@dtor-ws> References: <20160226184908.3539.48691.stgit@localhost.localdomain> <20160226185007.3539.83946.stgit@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-pa0-f54.google.com ([209.85.220.54]:33296 "EHLO mail-pa0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753495AbcBZT5u (ORCPT ); Fri, 26 Feb 2016 14:57:50 -0500 Received: by mail-pa0-f54.google.com with SMTP id fl4so55930638pad.0 for ; Fri, 26 Feb 2016 11:57:50 -0800 (PST) Content-Disposition: inline In-Reply-To: <20160226185007.3539.83946.stgit@localhost.localdomain> Sender: linux-input-owner@vger.kernel.org List-Id: linux-input@vger.kernel.org To: Alan Cc: linux-input@vger.kernel.org On Fri, Feb 26, 2016 at 06:50:21PM +0000, Alan wrote: > From: Lingfeng Yang > > If we send SYN_REPORT on every single multi-touch event, it breaks the > multi-touch. > > The multi-touch becomes jerky and you have to click 2-3 times to do things > while randomly activating notification bars when not clicking. > > If we suppress these SYN_REPORTS, multi-touch will work fine and the events > will have a protocol that looks nice. > > We need to register Goldfish Events as a multi-touch device by issuing > input_mt_init_slots, otherwise input_handle_abs_event in drivers/input/input.c > will silently drop all ABS_MT_SLOT events, causing touches of more than one > finger to fail. > > Signed-off-by: Lingfeng Yang > Signed-off-by: Jin Qian > Signed-off-by: Alan Cox > --- > drivers/input/keyboard/goldfish_events.c | 30 +++++++++++++++++++++++++++++- > 1 file changed, 29 insertions(+), 1 deletion(-) > > diff --git a/drivers/input/keyboard/goldfish_events.c b/drivers/input/keyboard/goldfish_events.c > index c7e308a..c0d77b7 100644 > --- a/drivers/input/keyboard/goldfish_events.c > +++ b/drivers/input/keyboard/goldfish_events.c > @@ -17,6 +17,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -24,6 +25,8 @@ > #include > #include > > +#define GOLDFISH_MAX_FINGERS 5 > + > enum { > REG_READ = 0x00, > REG_SET_PAGE = 0x00, > @@ -52,7 +55,23 @@ static irqreturn_t events_interrupt(int irq, void *dev_id) > value = __raw_readl(edev->addr + REG_READ); > > input_event(edev->input, type, code, value); > - input_sync(edev->input); > + /* > + * Send an extra (EV_SYN, SYN_REPORT, 0x0) event > + * if a key was pressed. Some keyboard device > + * drivers may only send the EV_KEY event and > + * not EV_SYN. That would be error in that keyboard driver and should be fixed. > + * Note that sending an extra SYN_REPORT is not > + * necessary nor correct protocol with other > + * devices such as touchscreens, which will send > + * their own SYN_REPORT's when sufficient event > + * information has been collected (e.g., for > + * touchscreens, when pressure and X/Y coordinates > + * have been received). Hence, we will only send > + * this extra SYN_REPORT if type == EV_KEY. > + */ > + if (type == EV_KEY) > + input_sync(edev->input); I'd rather we always rely on the host to send the SYN event. > + > return IRQ_HANDLED; > } > > @@ -154,6 +173,15 @@ static int events_probe(struct platform_device *pdev) > > input_dev->name = edev->name; > input_dev->id.bustype = BUS_HOST; > + /* > + * Set the Goldfish Device to be multi-touch. > + * If we do not issue input_mt_init_slots, > + * the kernel will filter out needed ABS_MT_SLOT > + * events when we touch the screen in more than one place, > + * preventing multi-touch with more than one finger from working. > + * See drivers/input/input.c:input_handle_abs_event. > + */ > + input_mt_init_slots(input_dev, GOLDFISH_MAX_FINGERS, 0); Can we use data retrieved by events_import_abs_params() to set up correct number of slots? Also we need error handling. And possibly retrieve correct properties to set pass to input_mt_init_slots()... > > events_import_bits(edev, input_dev->evbit, EV_SYN, EV_MAX); > events_import_bits(edev, input_dev->keybit, EV_KEY, KEY_MAX); > Thanks. -- Dmitry