From: Andrew Lunn <andrew@lunn.ch>
To: Takashi Iwai <tiwai@suse.de>
Cc: Hans Verkuil <hverkuil@xs4all.nl>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
"Matwey V. Kornilov" <matwey@sai.msu.ru>,
Robert Foss <robert.foss@linaro.org>
Subject: Re: [PATCH] media: pwc: Fix the URB buffer allocation
Date: Fri, 5 Feb 2021 14:13:02 +0100 [thread overview]
Message-ID: <YB1EXirrstMlg/vA@lunn.ch> (raw)
In-Reply-To: <s5h1rdu4qgo.wl-tiwai@suse.de>
Hi Takashi
> Indeed, looks so. In most cases, this doesn't matter since both point
> to the same device object. In some cases like xhci-plat HCD, they
> differ. And sysdev might be a better choice from the consistency
> POV.
>
> But this brought an interesting question, too. eg. USB chipidea
> HCD uses platform devices for both controller and sysdev, and I
> couldn't find any DMA mask setup. So, no matter what to use, the uwc
> driver would be broken on this... Maybe it's just not covered.
Did you do a git bisect to see what actually broke it? "1161db6776bd:
media: usb: pwc: Don't use coherent DMA buffers for ISO transfer"
introduced the code, not the regression. If we understand the
regression, that might give us the answer about chipidea.
Andrew
next prev parent reply other threads:[~2021-02-05 13:19 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-21 20:28 [PATCH] media: pwc: Fix the URB buffer allocation Takashi Iwai
2021-01-22 8:57 ` Robert Foss
2021-02-05 12:36 ` Hans Verkuil
2021-02-05 12:53 ` Andrew Lunn
2021-02-05 13:03 ` Takashi Iwai
2021-02-05 13:13 ` Andrew Lunn [this message]
2021-02-05 13:42 ` Takashi Iwai
2021-02-05 13:53 ` Andrew Lunn
2021-02-05 14:05 ` Hans Verkuil
2021-02-05 14:19 ` Takashi Iwai
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