From: Vasily Khoruzhick <anarsoul@gmail.com>

Some adapters (e.g. RTL8723CS) advertise that they have more than
2 pages for local ext features, but they don't support any features
declared in these pages. RTL8723CS reports max_page = 2 and declares
support for sync train and secure connection, but it responds with
either garbage or with error in status on corresponding commands.

Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
Signed-off-by: Bastian Germann <bage@debian.org>
---
 include/net/bluetooth/hci.h | 7 +++++++
 net/bluetooth/hci_event.c   | 4 +++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 8d773b042c85..7127313140cf 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -294,6 +294,13 @@ enum {
 	 * during the hdev->setup vendor callback.
 	 */
 	HCI_QUIRK_BROKEN_MWS_TRANSPORT_CONFIG,
+
+	/* When this quirk is set, max_page for local extended features
+	 * is set to 1, even if controller reports higher number. Some
+	 * controllers (e.g. RTL8723CS) report more pages, but they
+	 * don't actually support features declared there.
+	 */
+	HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES_PAGE_2,
 };
 
 /* HCI device flags */
diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
index ad92a4be5851..83ebc8e65b42 100644
--- a/net/bluetooth/hci_event.c
+++ b/net/bluetooth/hci_event.c
@@ -886,7 +886,9 @@ static u8 hci_cc_read_local_ext_features(struct hci_dev *hdev, void *data,
 	if (rp->status)
 		return rp->status;
 
-	if (hdev->max_page < rp->max_page)
+	if (!test_bit(HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES_PAGE_2,
+		      &hdev->quirks) &&
+	    hdev->max_page < rp->max_page)
 		hdev->max_page = rp->max_page;
 
 	if (rp->page < HCI_MAX_PAGES)
-- 
2.39.1

Hi Bastien,

On Mon, Feb 6, 2023 at 3:39 PM Bastian Germann <bage@debian.org> wrote:
>
> From: Vasily Khoruzhick <anarsoul@gmail.com>
>
> Some adapters (e.g. RTL8723CS) advertise that they have more than
> 2 pages for local ext features, but they don't support any features
> declared in these pages. RTL8723CS reports max_page = 2 and declares
> support for sync train and secure connection, but it responds with
> either garbage or with error in status on corresponding commands.
>
> Signed-off-by: Vasily Khoruzhick <anarsoul@gmail.com>
> Signed-off-by: Bastian Germann <bage@debian.org>
> ---
>  include/net/bluetooth/hci.h | 7 +++++++
>  net/bluetooth/hci_event.c   | 4 +++-
>  2 files changed, 10 insertions(+), 1 deletion(-)
>
> diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
> index 8d773b042c85..7127313140cf 100644
> --- a/include/net/bluetooth/hci.h
> +++ b/include/net/bluetooth/hci.h
> @@ -294,6 +294,13 @@ enum {
>          * during the hdev->setup vendor callback.
>          */
>         HCI_QUIRK_BROKEN_MWS_TRANSPORT_CONFIG,
> +
> +       /* When this quirk is set, max_page for local extended features
> +        * is set to 1, even if controller reports higher number. Some
> +        * controllers (e.g. RTL8723CS) report more pages, but they
> +        * don't actually support features declared there.
> +        */
> +       HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES_PAGE_2,
>  };
>
>  /* HCI device flags */
> diff --git a/net/bluetooth/hci_event.c b/net/bluetooth/hci_event.c
> index ad92a4be5851..83ebc8e65b42 100644
> --- a/net/bluetooth/hci_event.c
> +++ b/net/bluetooth/hci_event.c
> @@ -886,7 +886,9 @@ static u8 hci_cc_read_local_ext_features(struct hci_dev *hdev, void *data,
>         if (rp->status)
>                 return rp->status;
>
> -       if (hdev->max_page < rp->max_page)
> +       if (!test_bit(HCI_QUIRK_BROKEN_LOCAL_EXT_FEATURES_PAGE_2,
> +                     &hdev->quirks) &&
> +           hdev->max_page < rp->max_page)
>                 hdev->max_page = rp->max_page;
>
>         if (rp->page < HCI_MAX_PAGES)
> --
> 2.39.1

Looks like I never replied to this one, we might want to add a warning
when the controller requires such quirks since the manufacturer is
supposed to fix this in their firmware.



-- 
Luiz Augusto von Dentz