xen-devel.lists.xenproject.org archive mirror
 help / color / mirror / Atom feed
From: Connor Davis <connojdavis@gmail.com>
To: Jan Beulich <jbeulich@suse.com>
Cc: Jann Horn <jannh@google.com>, Lee Jones <lee.jones@linaro.org>,
	Chunfeng Yun <chunfeng.yun@mediatek.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	xen-devel@lists.xenproject.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Subject: Re: [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled
Date: Mon, 17 May 2021 07:48:52 -0600	[thread overview]
Message-ID: <16400ee4-4406-8b26-10c0-a423b2b1fed0@gmail.com> (raw)
In-Reply-To: <8ccce25a-e3ca-cb30-f6a3-f9243a85a49b@suse.com>


On 5/17/21 3:32 AM, Jan Beulich wrote:
> On 14.05.2021 02:56, Connor Davis wrote:
>> Check if the debug capability is enabled in early_xdbc_parse_parameter,
>> and if it is, return with an error. This avoids collisions with whatever
>> enabled the DbC prior to linux starting.
> Doesn't this go too far and prevent use even if firmware (perhaps
> mistakenly) left it enabled?
>
> Jan

Yes, but how is one supposed to distinguish the broken firmware and 
non-broken

firmware cases?

>
>> Signed-off-by: Connor Davis <connojdavis@gmail.com>
>> ---
>>   drivers/usb/early/xhci-dbc.c | 10 ++++++++++
>>   1 file changed, 10 insertions(+)
>>
>> diff --git a/drivers/usb/early/xhci-dbc.c b/drivers/usb/early/xhci-dbc.c
>> index be4ecbabdd58..ca67fddc2d36 100644
>> --- a/drivers/usb/early/xhci-dbc.c
>> +++ b/drivers/usb/early/xhci-dbc.c
>> @@ -642,6 +642,16 @@ int __init early_xdbc_parse_parameter(char *s)
>>   	}
>>   	xdbc.xdbc_reg = (struct xdbc_regs __iomem *)(xdbc.xhci_base + offset);
>>   
>> +	if (readl(&xdbc.xdbc_reg->control) & CTRL_DBC_ENABLE) {
>> +		pr_notice("xhci debug capability already in use\n");
>> +		early_iounmap(xdbc.xhci_base, xdbc.xhci_length);
>> +		xdbc.xdbc_reg = NULL;
>> +		xdbc.xhci_base = NULL;
>> +		xdbc.xhci_length = 0;
>> +
>> +		return -ENODEV;
>> +	}
>> +
>>   	return 0;
>>   }
>>   
>>
Thanks,

Connor



  reply	other threads:[~2021-05-17 13:48 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-14  0:56 [PATCH v2 0/4] Support xen-driven USB3 debug capability Connor Davis
2021-05-14  0:56 ` [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled Connor Davis
2021-05-14  0:56   ` [PATCH v2 2/4] xen: Export dbgp functions when CONFIG_XEN_DOM0 is enabled Connor Davis
2021-05-14 14:06     ` Connor Davis
2021-05-14  0:56   ` [PATCH v2 3/4] usb: dbgp: Fix return values for reset prep and startup Connor Davis
2021-05-14 15:33     ` Boris Ostrovsky
2021-05-17  9:32   ` [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled Jan Beulich
2021-05-17 13:48     ` Connor Davis [this message]
2021-05-17 14:13       ` Jan Beulich
2021-05-17 14:24         ` Connor Davis
2021-05-18 21:50           ` Mathias Nyman
2021-05-14  6:46 ` [PATCH v2 0/4] Support xen-driven USB3 debug capability Greg Kroah-Hartman
2021-05-14 14:07   ` Connor Davis

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=16400ee4-4406-8b26-10c0-a423b2b1fed0@gmail.com \
    --to=connojdavis@gmail.com \
    --cc=chunfeng.yun@mediatek.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=jannh@google.com \
    --cc=jbeulich@suse.com \
    --cc=lee.jones@linaro.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=xen-devel@lists.xenproject.org \
    --subject='Re: [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).