linux-kernel - [PATCH] USB: core: hub_port_reset: Remove extra 40 ms reset recovery time

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Message-ID: <20240724111524.25441-1-pmenzel@molgen.mpg.de>
Date: Wed, 24 Jul 2024 13:15:23 +0200
From: Paul Menzel <pmenzel@...gen.mpg.de>
To: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	David Brownell <david-b@...bell.net>
Cc: Paul Menzel <pmenzel@...gen.mpg.de>,
	Kai-Heng Feng <kai.heng.feng@...onical.com>,
	Hans de Goede <hdegoede@...hat.com>,
	Greg Kroah-Hartman <gregkh@...e.de>,
	linux-usb@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] USB: core: hub_port_reset: Remove extra 40 ms reset recovery time

This basically reverts commit b789696af8b4102b7cc26dec30c2c51ce51ee18b
("[PATCH] USB: relax usbcore reset timings") from 2005.

This adds unneeded 40 ms during resume from suspend on a majority of
devices, where it’s not needed, like the Dell XPS 13 9360/0596KF, BIOS
2.21.0 06/02/2022 with

    $ usb-devices

    T:  Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=480  MxCh=12
    D:  Ver= 2.00 Cls=09(hub  ) Sub=00 Prot=01 MxPS=64 #Cfgs=  1
    P:  Vendor=1d6b ProdID=0002 Rev=06.09
    S:  Manufacturer=Linux 6.9.0-rc6-00047-g25a99e110f17 xhci-hcd
    S:  Product=xHCI Host Controller
    S:  SerialNumber=0000:00:14.0
    C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
    I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
    E:  Ad=81(I) Atr=03(Int.) MxPS=   4 Ivl=256ms

    T:  Bus=01 Lev=01 Prnt=01 Port=02 Cnt=01 Dev#=  2 Spd=12   MxCh= 0
    D:  Ver= 2.01 Cls=e0(wlcon) Sub=01 Prot=01 MxPS=64 #Cfgs=  1
    P:  Vendor=0cf3 ProdID=e300 Rev=00.01
    C:  #Ifs= 2 Cfg#= 1 Atr=e0 MxPwr=100mA
    I:  If#= 0 Alt= 0 #EPs= 3 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
    E:  Ad=02(O) Atr=02(Bulk) MxPS=  64 Ivl=0ms
    E:  Ad=81(I) Atr=03(Int.) MxPS=  16 Ivl=1ms
    E:  Ad=82(I) Atr=02(Bulk) MxPS=  64 Ivl=0ms
    I:  If#= 1 Alt= 0 #EPs= 2 Cls=e0(wlcon) Sub=01 Prot=01 Driver=btusb
    E:  Ad=03(O) Atr=01(Isoc) MxPS=   0 Ivl=1ms
    E:  Ad=83(I) Atr=01(Isoc) MxPS=   0 Ivl=1ms

    T:  Bus=01 Lev=01 Prnt=02 Port=03 Cnt=01 Dev#=  3 Spd=12   MxCh= 0
    D:  Ver= 2.00 Cls=00(>ifc ) Sub=00 Prot=00 MxPS= 8 #Cfgs=  1
    P:  Vendor=04f3 ProdID=2234 Rev=11.11
    S:  Manufacturer=ELAN
    S:  Product=Touchscreen
    C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=100mA
    I:  If#= 0 Alt= 0 #EPs= 2 Cls=03(HID  ) Sub=00 Prot=00 Driver=usbhid
    E:  Ad=02(O) Atr=03(Int.) MxPS=  32 Ivl=2ms
    E:  Ad=81(I) Atr=03(Int.) MxPS=  64 Ivl=1ms

    T:  Bus=01 Lev=01 Prnt=03 Port=04 Cnt=01 Dev#=  4 Spd=480  MxCh= 0
    D:  Ver= 2.01 Cls=ef(misc ) Sub=02 Prot=01 MxPS=64 #Cfgs=  1
    P:  Vendor=0c45 ProdID=670c Rev=56.26
    S:  Manufacturer=CN09GTFMLOG008C8B7FWA01
    S:  Product=Integrated_Webcam_HD
    C:  #Ifs= 2 Cfg#= 1 Atr=80 MxPwr=500mA
    I:  If#= 0 Alt= 0 #EPs= 1 Cls=0e(video) Sub=01 Prot=00 Driver=uvcvideo
    E:  Ad=83(I) Atr=03(Int.) MxPS=  16 Ivl=4ms
    I:  If#= 1 Alt= 0 #EPs= 1 Cls=0e(video) Sub=02 Prot=00 Driver=uvcvideo
    E:  Ad=82(I) Atr=02(Bulk) MxPS= 512 Ivl=0ms

    T:  Bus=02 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#=  1 Spd=5000 MxCh= 6
    D:  Ver= 3.00 Cls=09(hub  ) Sub=00 Prot=03 MxPS= 9 #Cfgs=  1
    P:  Vendor=1d6b ProdID=0003 Rev=06.09
    S:  Manufacturer=Linux 6.9.0-rc6-00047-g25a99e110f17 xhci-hcd
    S:  Product=xHCI Host Controller
    S:  SerialNumber=0000:00:14.0
    C:  #Ifs= 1 Cfg#= 1 Atr=e0 MxPwr=0mA
    I:  If#= 0 Alt= 0 #EPs= 1 Cls=09(hub  ) Sub=00 Prot=00 Driver=hub
    E:  Ad=81(I) Atr=03(Int.) MxPS=   4 Ivl=256ms

The commit messages unfortunately does not list the devices needing this.
Should they surface again, these should be added to the quirk list for
USB_QUIRK_HUB_SLOW_RESET.

Fixes: b789696af8b4 ("[PATCH] USB: relax usbcore reset timings")
Cc: Kai-Heng Feng <kai.heng.feng@...onical.com>
Cc: Hans de Goede <hdegoede@...hat.com>
Cc: David Brownell <david-b@...bell.net>
Signed-off-by: Paul Menzel <pmenzel@...gen.mpg.de>
---
 drivers/usb/core/hub.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 4b93c0bd1d4b..487d5fe60f0c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -3110,7 +3110,7 @@ static int hub_port_reset(struct usb_hub *hub, int port1,
 			usleep_range(10000, 12000);
 		else {
 			/* TRSTRCY = 10 ms; plus some extra */
-			reset_recovery_time = 10 + 40;
+			reset_recovery_time = 10;
 
 			/* Hub needs extra delay after resetting its port. */
 			if (hub->hdev->quirks & USB_QUIRK_HUB_SLOW_RESET)
-- 
2.45.2