| Message ID | 20210917122718.86776-1-verdre@v0yd.nl (mailing list archive) |
|---|---|
| State | Not Applicable |
| Delegated to: | Johannes Berg |
| Headers | show |
| Series | Bluetooth: btusb: Lower passive lescan interval on Marvell 88W8897 | expand |
On Friday 17 September 2021 14:27:18 Jonas Dreßler wrote: > The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) > is used in a lot of Microsoft Surface devices, and all those devices > suffer from very low 2.4GHz wifi connection speeds while bluetooth is > enabled. Hello! Do you know if this issue is specific only to this one Marvell 88W8897 chip or if this issue affects also other Marvell wifi+bt combo chips? > The reason for that is that the default passive scanning > interval for Bluetooth Low Energy devices is quite high on Linux > (interval of 60 msec and scan window of 30 msec, see le_scan_interval > and le_scan_window in hci_core.c), and the Marvell chip is known for its > bad bt+wifi coexisting performance. > > So decrease that passive scan interval and make the scan window shorter > on this particular device to allow for spending more time transmitting > wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and > the new scan window is 6.25 msec (0xa * 0.625 msec). > > This change has a very large impact on the 2.4GHz wifi speeds and gets > it up to performance comparable with the Windows driver, which seems to > apply a similar quirk. > > The scan interval and scan window length were tested and found to work > very well with a bunch of Bluetooth Low Energy devices, including the > Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. > All devices were discovered immediately after turning them on. Even > lower values were also tested, but these introduced longer delays until > devices get discovered. > > Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> > --- > drivers/bluetooth/btusb.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c > index 60d2fce59a71..05b11179c839 100644 > --- a/drivers/bluetooth/btusb.c > +++ b/drivers/bluetooth/btusb.c > @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; > #define BTUSB_WIDEBAND_SPEECH 0x400000 > #define BTUSB_VALID_LE_STATES 0x800000 > #define BTUSB_QCA_WCN6855 0x1000000 > +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 > #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 > > static const struct usb_device_id btusb_table[] = { > @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { > { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, > { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, > { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, > + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, > > /* Intel Bluetooth devices */ > { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, > @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, > if (id->driver_info & BTUSB_MARVELL) > hdev->set_bdaddr = btusb_set_bdaddr_marvell; > > + /* The Marvell 88W8897 combined wifi and bluetooth card is known for > + * very bad bt+wifi coexisting performance. > + * > + * Decrease the passive BT Low Energy scan interval a bit > + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter > + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly > + * higher wifi throughput while passively scanning for BT LE devices. > + */ > + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { > + hdev->le_scan_interval = 0x0190; > + hdev->le_scan_window = 0x000a; > + } > + > if (IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK) && > (id->driver_info & BTUSB_MEDIATEK)) { > hdev->setup = btusb_mtk_setup; > -- > 2.31.1 >
Hi Jonas, > The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) > is used in a lot of Microsoft Surface devices, and all those devices > suffer from very low 2.4GHz wifi connection speeds while bluetooth is > enabled. The reason for that is that the default passive scanning > interval for Bluetooth Low Energy devices is quite high on Linux > (interval of 60 msec and scan window of 30 msec, see le_scan_interval > and le_scan_window in hci_core.c), and the Marvell chip is known for its > bad bt+wifi coexisting performance. > > So decrease that passive scan interval and make the scan window shorter > on this particular device to allow for spending more time transmitting > wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and > the new scan window is 6.25 msec (0xa * 0.625 msec). > > This change has a very large impact on the 2.4GHz wifi speeds and gets > it up to performance comparable with the Windows driver, which seems to > apply a similar quirk. > > The scan interval and scan window length were tested and found to work > very well with a bunch of Bluetooth Low Energy devices, including the > Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. > All devices were discovered immediately after turning them on. Even > lower values were also tested, but these introduced longer delays until > devices get discovered. > > Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> > --- > drivers/bluetooth/btusb.c | 15 +++++++++++++++ > 1 file changed, 15 insertions(+) > > diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c > index 60d2fce59a71..05b11179c839 100644 > --- a/drivers/bluetooth/btusb.c > +++ b/drivers/bluetooth/btusb.c > @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; > #define BTUSB_WIDEBAND_SPEECH 0x400000 > #define BTUSB_VALID_LE_STATES 0x800000 > #define BTUSB_QCA_WCN6855 0x1000000 > +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 > #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 > > static const struct usb_device_id btusb_table[] = { > @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { > { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, > { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, > { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, > + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, > > /* Intel Bluetooth devices */ > { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, > @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, > if (id->driver_info & BTUSB_MARVELL) > hdev->set_bdaddr = btusb_set_bdaddr_marvell; > > + /* The Marvell 88W8897 combined wifi and bluetooth card is known for > + * very bad bt+wifi coexisting performance. > + * > + * Decrease the passive BT Low Energy scan interval a bit > + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter > + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly > + * higher wifi throughput while passively scanning for BT LE devices. > + */ > + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { > + hdev->le_scan_interval = 0x0190; > + hdev->le_scan_window = 0x000a; > + } > + you can not do it this way. Modifying hci_dev internals from within the driver is not acceptable. Regards Marcel
On 9/17/21 2:30 PM, Pali Rohár wrote: > On Friday 17 September 2021 14:27:18 Jonas Dreßler wrote: >> The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) >> is used in a lot of Microsoft Surface devices, and all those devices >> suffer from very low 2.4GHz wifi connection speeds while bluetooth is >> enabled. > > Hello! Do you know if this issue is specific only to this one Marvell > 88W8897 chip or if this issue affects also other Marvell wifi+bt combo > chips? Hi! No idea, good question, but I don't own any other devices with Marvell chips. Maybe it's even safe to apply it to all Bluetooth devices, I guess less scanning load is good for everyone (as long as it doesn't impact the scanning results of course, so that would need testing). > >> The reason for that is that the default passive scanning >> interval for Bluetooth Low Energy devices is quite high on Linux >> (interval of 60 msec and scan window of 30 msec, see le_scan_interval >> and le_scan_window in hci_core.c), and the Marvell chip is known for its >> bad bt+wifi coexisting performance. >> >> So decrease that passive scan interval and make the scan window shorter >> on this particular device to allow for spending more time transmitting >> wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and >> the new scan window is 6.25 msec (0xa * 0.625 msec). >> >> This change has a very large impact on the 2.4GHz wifi speeds and gets >> it up to performance comparable with the Windows driver, which seems to >> apply a similar quirk. >> >> The scan interval and scan window length were tested and found to work >> very well with a bunch of Bluetooth Low Energy devices, including the >> Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. >> All devices were discovered immediately after turning them on. Even >> lower values were also tested, but these introduced longer delays until >> devices get discovered. >> >> Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> >> --- >> drivers/bluetooth/btusb.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c >> index 60d2fce59a71..05b11179c839 100644 >> --- a/drivers/bluetooth/btusb.c >> +++ b/drivers/bluetooth/btusb.c >> @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; >> #define BTUSB_WIDEBAND_SPEECH 0x400000 >> #define BTUSB_VALID_LE_STATES 0x800000 >> #define BTUSB_QCA_WCN6855 0x1000000 >> +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 >> #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 >> >> static const struct usb_device_id btusb_table[] = { >> @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { >> { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, >> { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, >> { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, >> + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, >> >> /* Intel Bluetooth devices */ >> { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, >> @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, >> if (id->driver_info & BTUSB_MARVELL) >> hdev->set_bdaddr = btusb_set_bdaddr_marvell; >> >> + /* The Marvell 88W8897 combined wifi and bluetooth card is known for >> + * very bad bt+wifi coexisting performance. >> + * >> + * Decrease the passive BT Low Energy scan interval a bit >> + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter >> + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly >> + * higher wifi throughput while passively scanning for BT LE devices. >> + */ >> + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { >> + hdev->le_scan_interval = 0x0190; >> + hdev->le_scan_window = 0x000a; >> + } >> + >> if (IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK) && >> (id->driver_info & BTUSB_MEDIATEK)) { >> hdev->setup = btusb_mtk_setup; >> -- >> 2.31.1 >>
On 9/17/21 2:35 PM, Marcel Holtmann wrote: > Hi Jonas, > >> The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) >> is used in a lot of Microsoft Surface devices, and all those devices >> suffer from very low 2.4GHz wifi connection speeds while bluetooth is >> enabled. The reason for that is that the default passive scanning >> interval for Bluetooth Low Energy devices is quite high on Linux >> (interval of 60 msec and scan window of 30 msec, see le_scan_interval >> and le_scan_window in hci_core.c), and the Marvell chip is known for its >> bad bt+wifi coexisting performance. >> >> So decrease that passive scan interval and make the scan window shorter >> on this particular device to allow for spending more time transmitting >> wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and >> the new scan window is 6.25 msec (0xa * 0.625 msec). >> >> This change has a very large impact on the 2.4GHz wifi speeds and gets >> it up to performance comparable with the Windows driver, which seems to >> apply a similar quirk. >> >> The scan interval and scan window length were tested and found to work >> very well with a bunch of Bluetooth Low Energy devices, including the >> Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. >> All devices were discovered immediately after turning them on. Even >> lower values were also tested, but these introduced longer delays until >> devices get discovered. >> >> Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> >> --- >> drivers/bluetooth/btusb.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c >> index 60d2fce59a71..05b11179c839 100644 >> --- a/drivers/bluetooth/btusb.c >> +++ b/drivers/bluetooth/btusb.c >> @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; >> #define BTUSB_WIDEBAND_SPEECH 0x400000 >> #define BTUSB_VALID_LE_STATES 0x800000 >> #define BTUSB_QCA_WCN6855 0x1000000 >> +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 >> #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 >> >> static const struct usb_device_id btusb_table[] = { >> @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { >> { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, >> { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, >> { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, >> + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, >> >> /* Intel Bluetooth devices */ >> { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, >> @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, >> if (id->driver_info & BTUSB_MARVELL) >> hdev->set_bdaddr = btusb_set_bdaddr_marvell; >> >> + /* The Marvell 88W8897 combined wifi and bluetooth card is known for >> + * very bad bt+wifi coexisting performance. >> + * >> + * Decrease the passive BT Low Energy scan interval a bit >> + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter >> + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly >> + * higher wifi throughput while passively scanning for BT LE devices. >> + */ >> + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { >> + hdev->le_scan_interval = 0x0190; >> + hdev->le_scan_window = 0x000a; >> + } >> + > > you can not do it this way. Modifying hci_dev internals from within the driver is not acceptable. > > Regards > > Marcel > Hi Marcel, hmm okay, it seems to me that the intention of your commit bef64738e3fb87eabc6fbeededad0c44ea173384 was to allow configuring it on a per controller basis, also btusb changes a bunch of other hci_dev properties? Given that we also have to match by usb-id, I don't think there's another place to do that other than the usb driver, or is there? Jonas
Hi Jonas, >>> The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) >>> is used in a lot of Microsoft Surface devices, and all those devices >>> suffer from very low 2.4GHz wifi connection speeds while bluetooth is >>> enabled. The reason for that is that the default passive scanning >>> interval for Bluetooth Low Energy devices is quite high on Linux >>> (interval of 60 msec and scan window of 30 msec, see le_scan_interval >>> and le_scan_window in hci_core.c), and the Marvell chip is known for its >>> bad bt+wifi coexisting performance. >>> >>> So decrease that passive scan interval and make the scan window shorter >>> on this particular device to allow for spending more time transmitting >>> wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and >>> the new scan window is 6.25 msec (0xa * 0.625 msec). >>> >>> This change has a very large impact on the 2.4GHz wifi speeds and gets >>> it up to performance comparable with the Windows driver, which seems to >>> apply a similar quirk. >>> >>> The scan interval and scan window length were tested and found to work >>> very well with a bunch of Bluetooth Low Energy devices, including the >>> Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. >>> All devices were discovered immediately after turning them on. Even >>> lower values were also tested, but these introduced longer delays until >>> devices get discovered. >>> >>> Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> >>> --- >>> drivers/bluetooth/btusb.c | 15 +++++++++++++++ >>> 1 file changed, 15 insertions(+) >>> >>> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c >>> index 60d2fce59a71..05b11179c839 100644 >>> --- a/drivers/bluetooth/btusb.c >>> +++ b/drivers/bluetooth/btusb.c >>> @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; >>> #define BTUSB_WIDEBAND_SPEECH 0x400000 >>> #define BTUSB_VALID_LE_STATES 0x800000 >>> #define BTUSB_QCA_WCN6855 0x1000000 >>> +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 >>> #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 >>> >>> static const struct usb_device_id btusb_table[] = { >>> @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { >>> { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, >>> { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, >>> { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, >>> + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, >>> >>> /* Intel Bluetooth devices */ >>> { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, >>> @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, >>> if (id->driver_info & BTUSB_MARVELL) >>> hdev->set_bdaddr = btusb_set_bdaddr_marvell; >>> >>> + /* The Marvell 88W8897 combined wifi and bluetooth card is known for >>> + * very bad bt+wifi coexisting performance. >>> + * >>> + * Decrease the passive BT Low Energy scan interval a bit >>> + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter >>> + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly >>> + * higher wifi throughput while passively scanning for BT LE devices. >>> + */ >>> + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { >>> + hdev->le_scan_interval = 0x0190; >>> + hdev->le_scan_window = 0x000a; >>> + } >>> + >> you can not do it this way. Modifying hci_dev internals from within the driver is not acceptable. >> Regards >> Marcel > > > hmm okay, it seems to me that the intention of your commit bef64738e3fb87eabc6fbeededad0c44ea173384 was to allow configuring it on a per controller basis, also btusb changes a bunch of other hci_dev properties? Given that we also have to match by usb-id, I don't think there's another place to do that other than the usb driver, or is there? you can change most defaults via mgmt commands. The things the a driver should set in hci_dev is really limited and it only affects its ability to run as a transport driver. It shouldn’t deal with anything that is actually HCI upper layer operation. Regards Marcel
On 9/17/21 3:18 PM, Marcel Holtmann wrote: > Hi Jonas, > >>>> The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) >>>> is used in a lot of Microsoft Surface devices, and all those devices >>>> suffer from very low 2.4GHz wifi connection speeds while bluetooth is >>>> enabled. The reason for that is that the default passive scanning >>>> interval for Bluetooth Low Energy devices is quite high on Linux >>>> (interval of 60 msec and scan window of 30 msec, see le_scan_interval >>>> and le_scan_window in hci_core.c), and the Marvell chip is known for its >>>> bad bt+wifi coexisting performance. >>>> >>>> So decrease that passive scan interval and make the scan window shorter >>>> on this particular device to allow for spending more time transmitting >>>> wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and >>>> the new scan window is 6.25 msec (0xa * 0.625 msec). >>>> >>>> This change has a very large impact on the 2.4GHz wifi speeds and gets >>>> it up to performance comparable with the Windows driver, which seems to >>>> apply a similar quirk. >>>> >>>> The scan interval and scan window length were tested and found to work >>>> very well with a bunch of Bluetooth Low Energy devices, including the >>>> Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. >>>> All devices were discovered immediately after turning them on. Even >>>> lower values were also tested, but these introduced longer delays until >>>> devices get discovered. >>>> >>>> Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> >>>> --- >>>> drivers/bluetooth/btusb.c | 15 +++++++++++++++ >>>> 1 file changed, 15 insertions(+) >>>> >>>> diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c >>>> index 60d2fce59a71..05b11179c839 100644 >>>> --- a/drivers/bluetooth/btusb.c >>>> +++ b/drivers/bluetooth/btusb.c >>>> @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; >>>> #define BTUSB_WIDEBAND_SPEECH 0x400000 >>>> #define BTUSB_VALID_LE_STATES 0x800000 >>>> #define BTUSB_QCA_WCN6855 0x1000000 >>>> +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 >>>> #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 >>>> >>>> static const struct usb_device_id btusb_table[] = { >>>> @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { >>>> { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, >>>> { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, >>>> { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, >>>> + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, >>>> >>>> /* Intel Bluetooth devices */ >>>> { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, >>>> @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, >>>> if (id->driver_info & BTUSB_MARVELL) >>>> hdev->set_bdaddr = btusb_set_bdaddr_marvell; >>>> >>>> + /* The Marvell 88W8897 combined wifi and bluetooth card is known for >>>> + * very bad bt+wifi coexisting performance. >>>> + * >>>> + * Decrease the passive BT Low Energy scan interval a bit >>>> + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter >>>> + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly >>>> + * higher wifi throughput while passively scanning for BT LE devices. >>>> + */ >>>> + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { >>>> + hdev->le_scan_interval = 0x0190; >>>> + hdev->le_scan_window = 0x000a; >>>> + } >>>> + >>> you can not do it this way. Modifying hci_dev internals from within the driver is not acceptable. >>> Regards >>> Marcel >> >> >> hmm okay, it seems to me that the intention of your commit bef64738e3fb87eabc6fbeededad0c44ea173384 was to allow configuring it on a per controller basis, also btusb changes a bunch of other hci_dev properties? Given that we also have to match by usb-id, I don't think there's another place to do that other than the usb driver, or is there? > > you can change most defaults via mgmt commands. > > The things the a driver should set in hci_dev is really limited and it only affects its ability to run as a transport driver. It shouldn’t deal with anything that is actually HCI upper layer operation. > > Regards > > Marcel > Hmm, having users of this wifi chip run a script at boot doesn't sound great to me, or can you point me to somewhere in bluez where I could put a device-specific quirk for this? IMHO this is a real bug with the hardware that needs to be quirked somewhere, note that this is not a minor performance improvement, this bumps wifi 2.4ghz speeds up from 800 KB/s to >5 MB/s. Other than that, there's also the possibility of changing the kernel-wide defaults, but as mentioned in my other answer, I don't have enough hardware laying around to test that at all. Jonas
diff --git a/drivers/bluetooth/btusb.c b/drivers/bluetooth/btusb.c index 60d2fce59a71..05b11179c839 100644 --- a/drivers/bluetooth/btusb.c +++ b/drivers/bluetooth/btusb.c @@ -59,6 +59,7 @@ static struct usb_driver btusb_driver; #define BTUSB_WIDEBAND_SPEECH 0x400000 #define BTUSB_VALID_LE_STATES 0x800000 #define BTUSB_QCA_WCN6855 0x1000000 +#define BTUSB_LOWER_LESCAN_INTERVAL 0x2000000 #define BTUSB_INTEL_BROKEN_INITIAL_NCMD 0x4000000 static const struct usb_device_id btusb_table[] = { @@ -356,6 +357,7 @@ static const struct usb_device_id blacklist_table[] = { { USB_DEVICE(0x1286, 0x2044), .driver_info = BTUSB_MARVELL }, { USB_DEVICE(0x1286, 0x2046), .driver_info = BTUSB_MARVELL }, { USB_DEVICE(0x1286, 0x204e), .driver_info = BTUSB_MARVELL }, + { USB_DEVICE(0x1286, 0x204c), .driver_info = BTUSB_LOWER_LESCAN_INTERVAL }, /* Intel Bluetooth devices */ { USB_DEVICE(0x8087, 0x0025), .driver_info = BTUSB_INTEL_COMBINED }, @@ -3813,6 +3815,19 @@ static int btusb_probe(struct usb_interface *intf, if (id->driver_info & BTUSB_MARVELL) hdev->set_bdaddr = btusb_set_bdaddr_marvell; + /* The Marvell 88W8897 combined wifi and bluetooth card is known for + * very bad bt+wifi coexisting performance. + * + * Decrease the passive BT Low Energy scan interval a bit + * (0x0190 * 0.625 msec = 250 msec) and make the scan window shorter + * (0x000a * 0,625 msec = 6.25 msec). This allows for significantly + * higher wifi throughput while passively scanning for BT LE devices. + */ + if (id->driver_info & BTUSB_LOWER_LESCAN_INTERVAL) { + hdev->le_scan_interval = 0x0190; + hdev->le_scan_window = 0x000a; + } + if (IS_ENABLED(CONFIG_BT_HCIBTUSB_MTK) && (id->driver_info & BTUSB_MEDIATEK)) { hdev->setup = btusb_mtk_setup;
The Marvell 88W8897 combined wifi and bluetooth card (pcie+usb version) is used in a lot of Microsoft Surface devices, and all those devices suffer from very low 2.4GHz wifi connection speeds while bluetooth is enabled. The reason for that is that the default passive scanning interval for Bluetooth Low Energy devices is quite high on Linux (interval of 60 msec and scan window of 30 msec, see le_scan_interval and le_scan_window in hci_core.c), and the Marvell chip is known for its bad bt+wifi coexisting performance. So decrease that passive scan interval and make the scan window shorter on this particular device to allow for spending more time transmitting wifi signals: The new scan interval is 250 msec (0x190 * 0.625 msec) and the new scan window is 6.25 msec (0xa * 0.625 msec). This change has a very large impact on the 2.4GHz wifi speeds and gets it up to performance comparable with the Windows driver, which seems to apply a similar quirk. The scan interval and scan window length were tested and found to work very well with a bunch of Bluetooth Low Energy devices, including the Surface Pen, a Bluetooth Speaker and two modern Bluetooth headphones. All devices were discovered immediately after turning them on. Even lower values were also tested, but these introduced longer delays until devices get discovered. Signed-off-by: Jonas Dreßler <verdre@v0yd.nl> --- drivers/bluetooth/btusb.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+)