From: Felipe Balbi <balbi@kernel.org>
To: Roger Quadros <rogerq@ti.com>,
gregkh@linuxfoundation.org, pawell@cadence.com
Cc: peter.chen@nxp.com, nsekhar@ti.com, kurahul@cadence.com,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2] usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host
Date: Thu, 31 Oct 2019 12:55:37 +0200 [thread overview]
Message-ID: <875zk5dw0m.fsf@gmail.com> (raw)
In-Reply-To: <44b07e90-a9de-ea99-25c6-dc72cf39bbe1@ti.com>
Hi,
Roger Quadros <rogerq@ti.com> writes:
> Hi,
>
> On 31/10/2019 10:55, Felipe Balbi wrote:
>>
>> Hi,
>>
>> Roger Quadros <rogerq@ti.com> writes:
>>
>>> Take into account gadget driver's speed limit when programming
>>> controller speed.
>>>
>>> Fixes: commit 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
>>> Signed-off-by: Roger Quadros <rogerq@ti.com>
>>> Acked-by: Peter Chen <peter.chen@nxp.com>
>>> ---
>>>
>>> Changelog:
>>> v2
>>> - Add Fixes line
>>>
>>> drivers/usb/cdns3/gadget.c | 31 ++++++++++++++++++++++++++-----
>>> 1 file changed, 26 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/usb/cdns3/gadget.c b/drivers/usb/cdns3/gadget.c
>>> index 40dad4e8d0dc..1c724c20d468 100644
>>> --- a/drivers/usb/cdns3/gadget.c
>>> +++ b/drivers/usb/cdns3/gadget.c
>>> @@ -2338,9 +2338,35 @@ static int cdns3_gadget_udc_start(struct usb_gadget *gadget,
>>> {
>>> struct cdns3_device *priv_dev = gadget_to_cdns3_device(gadget);
>>> unsigned long flags;
>>> + enum usb_device_speed max_speed = driver->max_speed;
>>>
>>> spin_lock_irqsave(&priv_dev->lock, flags);
>>> priv_dev->gadget_driver = driver;
>>> +
>>> + /* limit speed if necessary */
>>> + max_speed = min(driver->max_speed, gadget->max_speed);
>>> +
>>> + switch (max_speed) {
>>> + case USB_SPEED_FULL:
>>> + writel(USB_CONF_SFORCE_FS, &priv_dev->regs->usb_conf);
so this forces the controller to FS
>>> + writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
and this disconnects in superspeed? What is this supposed to do?
>>> + break;
>>> + case USB_SPEED_HIGH:
>>> + writel(USB_CONF_USB3DIS, &priv_dev->regs->usb_conf);
>>> + break;
>>> + case USB_SPEED_SUPER:
>>> + break;
>>> + default:
>>> + dev_err(priv_dev->dev,
>>> + "invalid maximum_speed parameter %d\n",
>>> + max_speed);
>>> + /* fall through */
>>> + case USB_SPEED_UNKNOWN:
>>> + /* default to superspeed */
>>> + max_speed = USB_SPEED_SUPER;
>>> + break;
>>> + }
>>
>> I had suggested some simplification for this case statement.
>>
>
> oops, looks like Greg picked this already.
>
> During more tests today I just observed that this patch causes
> the following regression.
>
> Connect EVM to Super-Speed host
> Load g_audio. (this enumerates as HS which is fine)
> unload g_audio
> load g_zero (this enumerates at HS instead of SS).
>
> This is because the speed limit that we set doesn't get cleared.
>
> Now the bits are write only and there is a way to undo USB_CONF_SFORCE_FS
> by writing USB_CONF_CFORCE_FS, however there is no corresponding bit
> to clear USB_CONF_USB3DIS. Only way seems to be USB_CFG_SWRST which
> is a bit harsh IMO.
Isn't bit 0 enough?
/* Reset USB device configuration. */
#define USB_CONF_CFGRST BIT(0)
Also, now that I look at this more carefully, you should move that code
to udc_set_speed().
--
balbi
next prev parent reply other threads:[~2019-10-31 10:55 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-29 15:15 [PATCH] usb: cdns3: gadget: Fix g_audio use case when connected to Super-Speed host Roger Quadros
2019-10-30 6:36 ` Peter Chen
2019-10-30 8:44 ` Roger Quadros
2019-10-30 8:56 ` Peter Chen
2019-10-30 11:46 ` Felipe Balbi
2019-10-30 11:51 ` Greg KH
2019-10-30 12:16 ` [PATCH v2] " Roger Quadros
2019-10-30 13:30 ` Greg KH
2019-10-30 14:20 ` Roger Quadros
2019-10-31 8:55 ` Felipe Balbi
2019-10-31 10:35 ` Roger Quadros
2019-10-31 10:55 ` Felipe Balbi [this message]
2019-10-31 11:02 ` Roger Quadros
2019-10-31 11:08 ` Felipe Balbi
2019-11-03 8:17 ` Pawel Laszczak
2019-11-04 9:18 ` Roger Quadros
2019-11-04 15:16 ` Pawel Laszczak
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