HID: core: move Usage Page concatenation to hid_parser_main()
diff mbox series

Message ID 20190312093652.12829-1-nsaenzjulienne@suse.de
State Superseded
Headers show
Series
  • HID: core: move Usage Page concatenation to hid_parser_main()
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Commit Message

Nicolas Saenz Julienne March 12, 2019, 9:36 a.m. UTC
As seen on some USB wireless keyboards manufactured by Primax, the HID
parser was using some assumptions that are not always true. In this case
it's s the fact that, inside the scope of a main item, an Usage Page
will always precede an Usage.

The spec is not pretty clear as 6.2.2.7 states "Any usage that follows
is interpreted as a Usage ID and concatenated with the Usage Page".
While 6.2.2.8 states "When the parser encounters a main item it
concatenates the last declared Usage Page with a Usage to form a
complete usage value." Being somewhat contradictory it was decided to
match Window's implementation, which follows 6.2.2.8.

In summary, the patch moves the Usage Page concatenation from the local
item parsing function to the main item parsing function.

Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
---

Note: A PR in hid-tools shoud show up anytime soon

 drivers/hid/hid-core.c | 30 ++++++++++++++++++------------
 include/linux/hid.h    |  1 +
 2 files changed, 19 insertions(+), 12 deletions(-)

Comments

Benjamin Tissoires March 25, 2019, 10:39 a.m. UTC | #1
Hi Nicolas,

On Tue, Mar 12, 2019 at 10:37 AM Nicolas Saenz Julienne
<nsaenzjulienne@suse.de> wrote:
>
> As seen on some USB wireless keyboards manufactured by Primax, the HID
> parser was using some assumptions that are not always true. In this case
> it's s the fact that, inside the scope of a main item, an Usage Page
> will always precede an Usage.
>
> The spec is not pretty clear as 6.2.2.7 states "Any usage that follows
> is interpreted as a Usage ID and concatenated with the Usage Page".
> While 6.2.2.8 states "When the parser encounters a main item it
> concatenates the last declared Usage Page with a Usage to form a
> complete usage value." Being somewhat contradictory it was decided to
> match Window's implementation, which follows 6.2.2.8.
>
> In summary, the patch moves the Usage Page concatenation from the local
> item parsing function to the main item parsing function.
>
> Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> ---

Patch looks good to me.

Terry, did you have time to review it?

Cheers,
Benjamin

>
> Note: A PR in hid-tools shoud show up anytime soon
>
>  drivers/hid/hid-core.c | 30 ++++++++++++++++++------------
>  include/linux/hid.h    |  1 +
>  2 files changed, 19 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> index 9993b692598f..158468ef23a6 100644
> --- a/drivers/hid/hid-core.c
> +++ b/drivers/hid/hid-core.c
> @@ -218,13 +218,14 @@ static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
>   * Add a usage to the temporary parser table.
>   */
>
> -static int hid_add_usage(struct hid_parser *parser, unsigned usage)
> +static int hid_add_usage(struct hid_parser *parser, unsigned usage, __u8 size)
>  {
>         if (parser->local.usage_index >= HID_MAX_USAGES) {
>                 hid_err(parser->device, "usage index exceeded\n");
>                 return -1;
>         }
>         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 ?
>                 parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
> @@ -486,10 +487,7 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
>                         return 0;
>                 }
>
> -               if (item->size <= 2)
> -                       data = (parser->global.usage_page << 16) + data;
> -
> -               return hid_add_usage(parser, data);
> +               return hid_add_usage(parser, data, item->size);
>
>         case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
>
> @@ -498,9 +496,6 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
>                         return 0;
>                 }
>
> -               if (item->size <= 2)
> -                       data = (parser->global.usage_page << 16) + data;
> -
>                 parser->local.usage_minimum = data;
>                 return 0;
>
> @@ -511,9 +506,6 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
>                         return 0;
>                 }
>
> -               if (item->size <= 2)
> -                       data = (parser->global.usage_page << 16) + data;
> -
>                 count = data - parser->local.usage_minimum;
>                 if (count + parser->local.usage_index >= HID_MAX_USAGES) {
>                         /*
> @@ -533,7 +525,7 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
>                 }
>
>                 for (n = parser->local.usage_minimum; n <= data; n++)
> -                       if (hid_add_usage(parser, n)) {
> +                       if (hid_add_usage(parser, n, item->size)) {
>                                 dbg_hid("hid_add_usage failed\n");
>                                 return -1;
>                         }
> @@ -553,8 +545,22 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
>
>  static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
>  {
> +       unsigned int usages;
>         __u32 data;
>         int ret;
> +       int i;
> +
> +       usages = max_t(unsigned, parser->local.usage_index,
> +                                parser->global.report_count);
> +
> +       /*
> +        * As per specification, 6.2.2.8:
> +        * "When the parser encounters a main item it concatenates the last
> +        * declared Usage Page with a Usage to form a complete usage value."
> +        */
> +       for (i = 0; i < usages; i++)
> +               if (parser->local.usage_size[i] <= 2)
> +                       parser->local.usage[i] += parser->global.usage_page << 16;
>
>         data = item_udata(item);
>
> diff --git a/include/linux/hid.h b/include/linux/hid.h
> index f9707d1dcb58..d1fb4b678873 100644
> --- a/include/linux/hid.h
> +++ b/include/linux/hid.h
> @@ -417,6 +417,7 @@ struct hid_global {
>
>  struct hid_local {
>         unsigned usage[HID_MAX_USAGES]; /* usage array */
> +       __u8 usage_size[HID_MAX_USAGES]; /* usage size array */
>         unsigned collection_index[HID_MAX_USAGES]; /* collection index array */
>         unsigned usage_index;
>         unsigned usage_minimum;
> --
> 2.21.0
>
Benjamin Tissoires March 25, 2019, 3:08 p.m. UTC | #2
On Mon, Mar 25, 2019 at 11:39 AM Benjamin Tissoires
<benjamin.tissoires@redhat.com> wrote:
>
> Hi Nicolas,
>
> On Tue, Mar 12, 2019 at 10:37 AM Nicolas Saenz Julienne
> <nsaenzjulienne@suse.de> wrote:
> >
> > As seen on some USB wireless keyboards manufactured by Primax, the HID
> > parser was using some assumptions that are not always true. In this case
> > it's s the fact that, inside the scope of a main item, an Usage Page
> > will always precede an Usage.
> >
> > The spec is not pretty clear as 6.2.2.7 states "Any usage that follows
> > is interpreted as a Usage ID and concatenated with the Usage Page".
> > While 6.2.2.8 states "When the parser encounters a main item it
> > concatenates the last declared Usage Page with a Usage to form a
> > complete usage value." Being somewhat contradictory it was decided to
> > match Window's implementation, which follows 6.2.2.8.
> >
> > In summary, the patch moves the Usage Page concatenation from the local
> > item parsing function to the main item parsing function.
> >
> > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> > ---
>
> Patch looks good to me.
>
> Terry, did you have time to review it?
>
> Cheers,
> Benjamin
>
> >
> > Note: A PR in hid-tools shoud show up anytime soon
> >
> >  drivers/hid/hid-core.c | 30 ++++++++++++++++++------------
> >  include/linux/hid.h    |  1 +
> >  2 files changed, 19 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > index 9993b692598f..158468ef23a6 100644
> > --- a/drivers/hid/hid-core.c
> > +++ b/drivers/hid/hid-core.c
> > @@ -218,13 +218,14 @@ static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
> >   * Add a usage to the temporary parser table.
> >   */
> >
> > -static int hid_add_usage(struct hid_parser *parser, unsigned usage)
> > +static int hid_add_usage(struct hid_parser *parser, unsigned usage, __u8 size)
> >  {
> >         if (parser->local.usage_index >= HID_MAX_USAGES) {
> >                 hid_err(parser->device, "usage index exceeded\n");
> >                 return -1;
> >         }
> >         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 ?
> >                 parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
> > @@ -486,10 +487,7 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
> >                         return 0;
> >                 }
> >
> > -               if (item->size <= 2)
> > -                       data = (parser->global.usage_page << 16) + data;
> > -
> > -               return hid_add_usage(parser, data);
> > +               return hid_add_usage(parser, data, item->size);
> >
> >         case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
> >
> > @@ -498,9 +496,6 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
> >                         return 0;
> >                 }
> >
> > -               if (item->size <= 2)
> > -                       data = (parser->global.usage_page << 16) + data;
> > -
> >                 parser->local.usage_minimum = data;
> >                 return 0;
> >
> > @@ -511,9 +506,6 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
> >                         return 0;
> >                 }
> >
> > -               if (item->size <= 2)
> > -                       data = (parser->global.usage_page << 16) + data;
> > -
> >                 count = data - parser->local.usage_minimum;
> >                 if (count + parser->local.usage_index >= HID_MAX_USAGES) {
> >                         /*
> > @@ -533,7 +525,7 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
> >                 }
> >
> >                 for (n = parser->local.usage_minimum; n <= data; n++)
> > -                       if (hid_add_usage(parser, n)) {
> > +                       if (hid_add_usage(parser, n, item->size)) {
> >                                 dbg_hid("hid_add_usage failed\n");
> >                                 return -1;
> >                         }
> > @@ -553,8 +545,22 @@ static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
> >
> >  static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
> >  {
> > +       unsigned int usages;
> >         __u32 data;
> >         int ret;
> > +       int i;
> > +
> > +       usages = max_t(unsigned, parser->local.usage_index,
> > +                                parser->global.report_count);
> > +
> > +       /*
> > +        * As per specification, 6.2.2.8:
> > +        * "When the parser encounters a main item it concatenates the last
> > +        * declared Usage Page with a Usage to form a complete usage value."
> > +        */
> > +       for (i = 0; i < usages; i++)
> > +               if (parser->local.usage_size[i] <= 2)
> > +                       parser->local.usage[i] += parser->global.usage_page << 16;

Actually, the good thing of having a test suite, is that it raises bugs :)

You are also missing the computation of the usage in hid_scan_main().
This makes the autoloading of hid-multitouch fail, and thus the test
suite failing.

Cheers,
Benjamin

> >
> >         data = item_udata(item);
> >
> > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > index f9707d1dcb58..d1fb4b678873 100644
> > --- a/include/linux/hid.h
> > +++ b/include/linux/hid.h
> > @@ -417,6 +417,7 @@ struct hid_global {
> >
> >  struct hid_local {
> >         unsigned usage[HID_MAX_USAGES]; /* usage array */
> > +       __u8 usage_size[HID_MAX_USAGES]; /* usage size array */
> >         unsigned collection_index[HID_MAX_USAGES]; /* collection index array */
> >         unsigned usage_index;
> >         unsigned usage_minimum;
> > --
> > 2.21.0
> >
Nicolas Saenz Julienne March 25, 2019, 3:12 p.m. UTC | #3
Hi Benjamin, Thanks for the review!

On Mon, 2019-03-25 at 16:08 +0100, Benjamin Tissoires wrote:
> On Mon, Mar 25, 2019 at 11:39 AM Benjamin Tissoires
> <benjamin.tissoires@redhat.com> wrote:
> > Hi Nicolas,
> > 
> > On Tue, Mar 12, 2019 at 10:37 AM Nicolas Saenz Julienne
> > <nsaenzjulienne@suse.de> wrote:
> > > As seen on some USB wireless keyboards manufactured by Primax, the HID
> > > parser was using some assumptions that are not always true. In this case
> > > it's s the fact that, inside the scope of a main item, an Usage Page
> > > will always precede an Usage.
> > > 
> > > The spec is not pretty clear as 6.2.2.7 states "Any usage that follows
> > > is interpreted as a Usage ID and concatenated with the Usage Page".
> > > While 6.2.2.8 states "When the parser encounters a main item it
> > > concatenates the last declared Usage Page with a Usage to form a
> > > complete usage value." Being somewhat contradictory it was decided to
> > > match Window's implementation, which follows 6.2.2.8.
> > > 
> > > In summary, the patch moves the Usage Page concatenation from the local
> > > item parsing function to the main item parsing function.
> > > 
> > > Signed-off-by: Nicolas Saenz Julienne <nsaenzjulienne@suse.de>
> > > ---
> > 
> > Patch looks good to me.
> > 
> > Terry, did you have time to review it?
> > 
> > Cheers,
> > Benjamin
> > 
> > > Note: A PR in hid-tools shoud show up anytime soon
> > > 
> > >  drivers/hid/hid-core.c | 30 ++++++++++++++++++------------
> > >  include/linux/hid.h    |  1 +
> > >  2 files changed, 19 insertions(+), 12 deletions(-)
> > > 
> > > diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
> > > index 9993b692598f..158468ef23a6 100644
> > > --- a/drivers/hid/hid-core.c
> > > +++ b/drivers/hid/hid-core.c
> > > @@ -218,13 +218,14 @@ static unsigned hid_lookup_collection(struct
> > > hid_parser *parser, unsigned type)
> > >   * Add a usage to the temporary parser table.
> > >   */
> > > 
> > > -static int hid_add_usage(struct hid_parser *parser, unsigned usage)
> > > +static int hid_add_usage(struct hid_parser *parser, unsigned usage, __u8
> > > size)
> > >  {
> > >         if (parser->local.usage_index >= HID_MAX_USAGES) {
> > >                 hid_err(parser->device, "usage index exceeded\n");
> > >                 return -1;
> > >         }
> > >         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 ?
> > >                 parser->collection_stack[parser->collection_stack_ptr - 1]
> > > : 0;
> > > @@ -486,10 +487,7 @@ static int hid_parser_local(struct hid_parser
> > > *parser, struct hid_item *item)
> > >                         return 0;
> > >                 }
> > > 
> > > -               if (item->size <= 2)
> > > -                       data = (parser->global.usage_page << 16) + data;
> > > -
> > > -               return hid_add_usage(parser, data);
> > > +               return hid_add_usage(parser, data, item->size);
> > > 
> > >         case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
> > > 
> > > @@ -498,9 +496,6 @@ static int hid_parser_local(struct hid_parser *parser,
> > > struct hid_item *item)
> > >                         return 0;
> > >                 }
> > > 
> > > -               if (item->size <= 2)
> > > -                       data = (parser->global.usage_page << 16) + data;
> > > -
> > >                 parser->local.usage_minimum = data;
> > >                 return 0;
> > > 
> > > @@ -511,9 +506,6 @@ static int hid_parser_local(struct hid_parser *parser,
> > > struct hid_item *item)
> > >                         return 0;
> > >                 }
> > > 
> > > -               if (item->size <= 2)
> > > -                       data = (parser->global.usage_page << 16) + data;
> > > -
> > >                 count = data - parser->local.usage_minimum;
> > >                 if (count + parser->local.usage_index >= HID_MAX_USAGES) {
> > >                         /*
> > > @@ -533,7 +525,7 @@ static int hid_parser_local(struct hid_parser *parser,
> > > struct hid_item *item)
> > >                 }
> > > 
> > >                 for (n = parser->local.usage_minimum; n <= data; n++)
> > > -                       if (hid_add_usage(parser, n)) {
> > > +                       if (hid_add_usage(parser, n, item->size)) {
> > >                                 dbg_hid("hid_add_usage failed\n");
> > >                                 return -1;
> > >                         }
> > > @@ -553,8 +545,22 @@ static int hid_parser_local(struct hid_parser
> > > *parser, struct hid_item *item)
> > > 
> > >  static int hid_parser_main(struct hid_parser *parser, struct hid_item
> > > *item)
> > >  {
> > > +       unsigned int usages;
> > >         __u32 data;
> > >         int ret;
> > > +       int i;
> > > +
> > > +       usages = max_t(unsigned, parser->local.usage_index,
> > > +                                parser->global.report_count);
> > > +
> > > +       /*
> > > +        * As per specification, 6.2.2.8:
> > > +        * "When the parser encounters a main item it concatenates the
> > > last
> > > +        * declared Usage Page with a Usage to form a complete usage
> > > value."
> > > +        */
> > > +       for (i = 0; i < usages; i++)
> > > +               if (parser->local.usage_size[i] <= 2)
> > > +                       parser->local.usage[i] += parser-
> > > >global.usage_page << 16;
> 
> Actually, the good thing of having a test suite, is that it raises bugs :)
> 
> You are also missing the computation of the usage in hid_scan_main().
> This makes the autoloading of hid-multitouch fail, and thus the test
> suite failing.

Ok, I'll look into it and send a follow-up.

> Cheers,
> Benjamin
> 
> > >         data = item_udata(item);
> > > 
> > > diff --git a/include/linux/hid.h b/include/linux/hid.h
> > > index f9707d1dcb58..d1fb4b678873 100644
> > > --- a/include/linux/hid.h
> > > +++ b/include/linux/hid.h
> > > @@ -417,6 +417,7 @@ struct hid_global {
> > > 
> > >  struct hid_local {
> > >         unsigned usage[HID_MAX_USAGES]; /* usage array */
> > > +       __u8 usage_size[HID_MAX_USAGES]; /* usage size array */
> > >         unsigned collection_index[HID_MAX_USAGES]; /* collection index
> > > array */
> > >         unsigned usage_index;
> > >         unsigned usage_minimum;
> > > --
> > > 2.21.0
> > >

Patch
diff mbox series

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index 9993b692598f..158468ef23a6 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -218,13 +218,14 @@  static unsigned hid_lookup_collection(struct hid_parser *parser, unsigned type)
  * Add a usage to the temporary parser table.
  */
 
-static int hid_add_usage(struct hid_parser *parser, unsigned usage)
+static int hid_add_usage(struct hid_parser *parser, unsigned usage, __u8 size)
 {
 	if (parser->local.usage_index >= HID_MAX_USAGES) {
 		hid_err(parser->device, "usage index exceeded\n");
 		return -1;
 	}
 	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 ?
 		parser->collection_stack[parser->collection_stack_ptr - 1] : 0;
@@ -486,10 +487,7 @@  static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 			return 0;
 		}
 
-		if (item->size <= 2)
-			data = (parser->global.usage_page << 16) + data;
-
-		return hid_add_usage(parser, data);
+		return hid_add_usage(parser, data, item->size);
 
 	case HID_LOCAL_ITEM_TAG_USAGE_MINIMUM:
 
@@ -498,9 +496,6 @@  static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 			return 0;
 		}
 
-		if (item->size <= 2)
-			data = (parser->global.usage_page << 16) + data;
-
 		parser->local.usage_minimum = data;
 		return 0;
 
@@ -511,9 +506,6 @@  static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 			return 0;
 		}
 
-		if (item->size <= 2)
-			data = (parser->global.usage_page << 16) + data;
-
 		count = data - parser->local.usage_minimum;
 		if (count + parser->local.usage_index >= HID_MAX_USAGES) {
 			/*
@@ -533,7 +525,7 @@  static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 		}
 
 		for (n = parser->local.usage_minimum; n <= data; n++)
-			if (hid_add_usage(parser, n)) {
+			if (hid_add_usage(parser, n, item->size)) {
 				dbg_hid("hid_add_usage failed\n");
 				return -1;
 			}
@@ -553,8 +545,22 @@  static int hid_parser_local(struct hid_parser *parser, struct hid_item *item)
 
 static int hid_parser_main(struct hid_parser *parser, struct hid_item *item)
 {
+	unsigned int usages;
 	__u32 data;
 	int ret;
+	int i;
+
+	usages = max_t(unsigned, parser->local.usage_index,
+				 parser->global.report_count);
+
+	/*
+	 * As per specification, 6.2.2.8:
+	 * "When the parser encounters a main item it concatenates the last
+	 * declared Usage Page with a Usage to form a complete usage value."
+	 */
+	for (i = 0; i < usages; i++)
+		if (parser->local.usage_size[i] <= 2)
+			parser->local.usage[i] += parser->global.usage_page << 16;
 
 	data = item_udata(item);
 
diff --git a/include/linux/hid.h b/include/linux/hid.h
index f9707d1dcb58..d1fb4b678873 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -417,6 +417,7 @@  struct hid_global {
 
 struct hid_local {
 	unsigned usage[HID_MAX_USAGES]; /* usage array */
+	__u8 usage_size[HID_MAX_USAGES]; /* usage size array */
 	unsigned collection_index[HID_MAX_USAGES]; /* collection index array */
 	unsigned usage_index;
 	unsigned usage_minimum;