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Message-ID: <CAO-hwJ+ObCH_NPJd=Uy5uuVCpGzO7+iCSWnwPkoVt9H+8NHahA@mail.gmail.com>
Date: Tue, 22 Oct 2019 11:48:28 +0200
From: Benjamin Tissoires <benjamin.tissoires@...hat.com>
To: Candle Sun <candlesea@...il.com>
Cc: Jiri Kosina <jikos@...nel.org>,
Nicolas Saenz Julienne <nsaenzjulienne@...e.de>,
翟京 (Orson Zhai) <orson.zhai@...soc.com>,
"open list:HID CORE LAYER" <linux-input@...r.kernel.org>,
lkml <linux-kernel@...r.kernel.org>,
Candle Sun <candle.sun@...soc.com>,
Nianfu Bai <nianfu.bai@...soc.com>
Subject: Re: [PATCH v3] HID: core: check whether usage page item is after
usage id item
Hi Candle,
On Mon, Oct 21, 2019 at 9:54 AM Candle Sun <candlesea@...il.com> wrote:
>
> Hi,
>
>
> On Mon, Oct 21, 2019 at 3:38 PM Candle Sun <candlesea@...il.com> wrote:
> >
> > From: Candle Sun <candle.sun@...soc.com>
> >
> > Upstream commit 58e75155009c ("HID: core: move Usage Page concatenation
> > to Main item") adds support for Usage Page item after Usage ID items
> > (such as keyboards manufactured by Primax).
> >
> > Usage Page concatenation in Main item works well for following report
> > descriptor patterns:
> >
> > USAGE_PAGE (Keyboard) 05 07
> > USAGE_MINIMUM (Keyboard LeftControl) 19 E0
> > USAGE_MAXIMUM (Keyboard Right GUI) 29 E7
> > LOGICAL_MINIMUM (0) 15 00
> > LOGICAL_MAXIMUM (1) 25 01
> > REPORT_SIZE (1) 75 01
> > REPORT_COUNT (8) 95 08
> > INPUT (Data,Var,Abs) 81 02
> >
> > -------------
> >
> > USAGE_MINIMUM (Keyboard LeftControl) 19 E0
> > USAGE_MAXIMUM (Keyboard Right GUI) 29 E7
> > LOGICAL_MINIMUM (0) 15 00
> > LOGICAL_MAXIMUM (1) 25 01
> > REPORT_SIZE (1) 75 01
> > REPORT_COUNT (8) 95 08
> > USAGE_PAGE (Keyboard) 05 07
> > INPUT (Data,Var,Abs) 81 02
> >
> > But it makes the parser act wrong for the following report
> > descriptor pattern(such as some Gamepads):
> >
> > USAGE_PAGE (Button) 05 09
> > USAGE (Button 1) 09 01
> > USAGE (Button 2) 09 02
> > USAGE (Button 4) 09 04
> > USAGE (Button 5) 09 05
> > USAGE (Button 7) 09 07
> > USAGE (Button 8) 09 08
> > USAGE (Button 14) 09 0E
> > USAGE (Button 15) 09 0F
> > USAGE (Button 13) 09 0D
> > USAGE_PAGE (Consumer Devices) 05 0C
> > USAGE (Back) 0a 24 02
> > USAGE (HomePage) 0a 23 02
> > LOGICAL_MINIMUM (0) 15 00
> > LOGICAL_MAXIMUM (1) 25 01
> > REPORT_SIZE (1) 75 01
> > REPORT_COUNT (11) 95 0B
> > INPUT (Data,Var,Abs) 81 02
> >
> > With Usage Page concatenation in Main item, parser recognizes all the
> > 11 Usages as consumer keys, it is not the HID device's real intention.
> >
> > This patch adds usage_page_last to flag whether Usage Page is after
> > Usage ID items. usage_page_last is false default, it is set as true
> > once Usage Page item is encountered and is reverted by next Usage ID
> > item.
> >
> > Usage Page concatenation on the currently defined Usage Page will do
> > firstly in Local parsing when Usage ID items encountered.
> >
> > When Main item is parsing, concatenation will do again with last
> > defined Usage Page if usage_page_last flag is true.
> >
> > Signed-off-by: Candle Sun <candle.sun@...soc.com>
> > Signed-off-by: Nianfu Bai <nianfu.bai@...soc.com>
> > ---
> > Changes in v3:
> > - Rework the GET_COMPLETE_USAGE macro as static complete_usage()
> > function
> > - Add some code comments for usage_page_last
> >
> > Changes in v2:
> > - Update patch title
> > - Add GET_COMPLETE_USAGE macro
> > - Change the logic of checking whether to concatenate usage page again
> > in main parsing
> > ---
> > drivers/hid/hid-core.c | 42 +++++++++++++++++++++++++++++++++++++-----
> > include/linux/hid.h | 1 +
> > 2 files changed, 38 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > index 3eaee2c37931..779b7798dae8 100644
> > --- a/drivers/hid/hid-core.c
> > +++ b/drivers/hid/hid-core.c
> > @@ -211,6 +211,18 @@ static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
> > return 0; /* we know nothing about this usage type */
> > }
> >
> > +/*
> > + * Concatenate usage which defines 16 bits or less with the
> > + * currently defined usage page to form a 32 bit usage
> > + */
> > +
> > +static void complete_usage(struct hid_parser *parser, unsigned int index)
> > +{
> > + parser->local.usage[index] &= 0xFFFF;
> > + parser->local.usage[index] |=
> > + (parser->global.usage_page & 0xFFFF) << 16;
> > +}
> > +
> > /*
> > * Add a usage to the temporary parser table.
> > */
> > @@ -221,7 +233,18 @@ static int hid_add_usage(struct hid_parser *parser, unsigned usage, u8 size)
> > hid_err(parser->device, "usage index exceeded\n");
> > return -1;
> > }
> > - parser->local.usage[parser->local.usage_index] = usage;
This broke my CI, and it turns out that installing the patch on an
actual laptop, the touchpad, touchscreen were not present, nor any HID
devices plugged in.
Basically, complete_usage() doesn't append the usage, and now we are
never assigning a usage to any field.
> > +
> > + /*
> > + * If Usage item only includes usage id, concatenate it with
> > + * currently defined usage page and clear usage_page_last flag
> > + */
> > + if (size <= 2) {
> > + parser->local.usage_page_last = false;
> > + complete_usage(parser, parser->local.usage_index);
> > + } else {
> > + parser->local.usage[parser->local.usage_index] = usage;
> > + }
> > +
> > parser->local.usage_size[parser->local.usage_index] = size;
> > parser->local.collection_index[parser->local.usage_index] =
> > parser->collection_stack_ptr ?
> > @@ -366,6 +389,8 @@ static int hid_parser_global(struct hid_parser *parser, struct hid_item *item)
> >
> > case HID_GLOBAL_ITEM_TAG_USAGE_PAGE:
> > parser->global.usage_page = item_udata(item);
> > + /* Regard Usage Page is after Usage ID items */
> > + parser->local.usage_page_last = true;
> > return 0;
> >
> > case HID_GLOBAL_ITEM_TAG_LOGICAL_MINIMUM:
> > @@ -543,13 +568,20 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
> > * usage value."
> > */
> >
> > -static void hid_concatenate_usage_page(struct hid_parser *parser)
> > +static void hid_concatenate_last_usage_page(struct hid_parser *parser)
> > {
> > int i;
> >
> > + /*
> > + * Concatenate usage page again only on detecting some Usage Page
> > + * is really after Usage ID items
> > + */
> > + if (!parser->local.usage_page_last)
> > + return;
> > +
> > for (i = 0; i < parser->local.usage_index; i++)
> > if (parser->local.usage_size[i] <= 2)
> > - parser->local.usage[i] += parser->global.usage_page << 16;
> > + complete_usage(parser, i);
> > }
> >
> > /*
> > @@ -561,7 +593,7 @@ static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
> > __u32 data;
> > int ret;
> >
> > - hid_concatenate_usage_page(parser);
> > + hid_concatenate_last_usage_page(parser);
> >
> > data = item_udata(item);
> >
> > @@ -772,7 +804,7 @@ static int hid_scan_main(struct hid_parser *parser, struct hid_item *item)
> > __u32 data;
> > int i;
> >
> > - hid_concatenate_usage_page(parser);
> > + hid_concatenate_last_usage_page(parser);
> >
> > data = item_udata(item);
> >
> > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > index cd41f209043f..2e0ea2f7ec5c 100644
> > --- a/include/linux/hid.h
> > +++ b/include/linux/hid.h
> > @@ -412,6 +412,7 @@ struct hid_local {
> > unsigned usage_minimum;
> > unsigned delimiter_depth;
> > unsigned delimiter_branch;
> > + bool usage_page_last; /* whether usage page is after usage id */
> > };
> >
>
> Hi Benjamin,
> Here I still use the usage_page_last flag, not using following method
> you provided in v2:
>
> if ((parser->local.usage[parser->local.usage_index - 1] &
> HID_USAGE_PAGE) >> 16 == usage_page)
> return 0;
>
> Because last usage maybe one Extended Usage, some logic for checking
> it should be added.
> It will make the code obscure. Using one more member in struct
> hid_local is straightforward
> and maybe better.
Still not convinced by this. Please see below for a less intrusive
patch, which is also shorter.
---
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 63fdbf09b044..00ea04fb1be3 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -211,6 +211,18 @@ static unsigned hid_lookup_collection(struct
hid_parser *parser, unsigned type)
return 0; /* we know nothing about this usage type */
}
+/*
+ * Concatenate usage which defines 16 bits or less with the
+ * currently defined usage page to form a 32 bit usage
+ */
+
+static void complete_usage(struct hid_parser *parser, unsigned int index)
+{
+ parser->local.usage[index] &= 0xFFFF;
+ parser->local.usage[index] |=
+ (parser->global.usage_page & 0xFFFF) << 16;
+}
+
/*
* Add a usage to the temporary parser table.
*/
@@ -222,6 +234,14 @@ static int hid_add_usage(struct hid_parser
*parser, unsigned usage, u8 size)
return -1;
}
parser->local.usage[parser->local.usage_index] = usage;
+
+ /*
+ * If Usage item only includes usage id, concatenate it with
+ * currently defined usage page
+ */
+ if (size <= 2)
+ complete_usage(parser, parser->local.usage_index);
+
parser->local.usage_size[parser->local.usage_index] = size;
parser->local.collection_index[parser->local.usage_index] =
parser->collection_stack_ptr ?
@@ -546,10 +566,28 @@ static int hid_parser_local(struct hid_parser
*parser, struct hid_item *item)
static void hid_concatenate_usage_page(struct hid_parser *parser)
{
int i;
+ uint16_t usage_page, current_page;
- for (i = 0; i < parser->local.usage_index; i++)
- if (parser->local.usage_size[i] <= 2)
- parser->local.usage[i] += parser->global.usage_page << 16;
+ if (!parser->local.usage_index)
+ return;
+
+ usage_page = parser->global.usage_page;
+
+ /*
+ * Concatenate usage page again only if the last declared Usage Page
+ * has not been already used in the previous Usages
+ */
+ for (i = parser->local.usage_index - 1; i >= 0; i--) {
+ if (parser->local.usage_size[i] > 2)
+ /* ignore extended usages */
+ continue;
+
+ current_page = parser->local.usage[i] >> 16;
+ if (current_page == usage_page)
+ break;
+
+ complete_usage(parser, i);
+ }
}
/*
---
Isn't that better?
I tested this against
https://gitlab.freedesktop.org/libevdev/hid-tools/merge_requests/58,
which you kindly submitted and it seems to do the job.
Cheers,
Benjamin
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