From: Jan Beulich <jbeulich@suse.com>
To: Connor Davis <connojdavis@gmail.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 11:32:01 +0200 [thread overview]
Message-ID: <8ccce25a-e3ca-cb30-f6a3-f9243a85a49b@suse.com> (raw)
In-Reply-To: <d160cee9b61c0ec41c2cd5ff9b4e107011d39d8c.1620952511.git.connojdavis@gmail.com>
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
> 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;
> }
>
>
next prev parent reply other threads:[~2021-05-17 9:32 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 ` Jan Beulich [this message]
2021-05-17 13:48 ` [PATCH v2 1/4] usb: early: Avoid using DbC if already enabled Connor Davis
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=8ccce25a-e3ca-cb30-f6a3-f9243a85a49b@suse.com \
--to=jbeulich@suse.com \
--cc=chunfeng.yun@mediatek.com \
--cc=connojdavis@gmail.com \
--cc=gregkh@linuxfoundation.org \
--cc=jannh@google.com \
--cc=lee.jones@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=xen-devel@lists.xenproject.org \
/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
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
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).