From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0481B189B84; Mon, 21 Apr 2025 08:51:41 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745225502; cv=none; b=RxfZJFlC8d22nvtoPFDtmvb2vlEBmJ2Ic6GuC6rO54a08zYATah7jlYgnl3XXa+CLB4V7kAx7F0HaF2sc2iqA66f/gNPJy0qgPc59Z+KGWm/ZaX8RBqLvnPECLilHV+mFrpIeqfJh0CgA8di7Oo6pCGWZlkEzzbwC/sevMO2Tok= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745225502; c=relaxed/simple; bh=zJShDvas9o4kwADRZZXz3VeLI3YlnhE4uY/hWs9kiJg=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=dbEewFqG/Uu3chi2PV+Q9kCZgB7DRg3+yu4y5aSpXqdTdjivcwCwXlNPpnIU/s2Qr5AKFTRKWduvQgiCExzHGG2e1IvwykR1134QEr7RitQrJJ67ijsp9/ijn7R7A1CVQMJukW4choy6vU2s4aFzjujdeySpxNktVTdqx3RWzAA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=o0001Z8v; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="o0001Z8v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0042CC4CEE4; Mon, 21 Apr 2025 08:51:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1745225501; bh=zJShDvas9o4kwADRZZXz3VeLI3YlnhE4uY/hWs9kiJg=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=o0001Z8vypGe599+bJD9siWiB4gPa+3L0luwFQlHRmj4wgNTPZvnZdgfl4F9aTJrv EqDk1WcvM7uIw3g+4G2gcltTiMYF+SXbq+f/n/LZmGkACLVvjPi22D4H3DXBSI/8+2 Yw5PS1UOv27xv3L6l2IfKRscOQyc5pNG8X0x0CkM= Date: Mon, 21 Apr 2025 10:51:38 +0200 From: Greg KH To: Michal Pecio Cc: Laurent Pinchart , Hans de Goede , Mauro Carvalho Chehab , linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: Re: [PATCH] media: uvcvideo: Support large SuperSpeedPlus isochronous endpoints Message-ID: <2025042101-coyness-vitality-e636@gregkh> References: <20250421095951.1e63824e@foxbook> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250421095951.1e63824e@foxbook> On Mon, Apr 21, 2025 at 09:59:51AM +0200, Michal Pecio wrote: > USB 3.1 increased maximum isochronous bandwidth to 96KB per interval, > too much for 16 bits and the SuperSpeed Endpoint Companion descriptor. > A new SuperSpeedPlus Isochronous Endpoint Companion descriptor was > introduced to encode such bandwidths, see spec sections 9.6.7, 9.6.8. > > Support the descriptor with code based on xhci_get_max_esit_payload() > and widen all 'psize' variables to 32 bits. Subsequent calculations > are 32 bit already and not expected to overflow, so this change ought > to suffice for proper alt setting selection on USB 3.x Gen 2 devices. > > Signed-off-by: Michal Pecio > --- > > This change appears to be a strict necessity for supporting USB3 Gen2 > isochronous devices meaningfully. Whether it's sufficient I don't know, > I don't have such HW. No regression seen on High Speed and SuperSpeed. If you don't have the hardware, why make this change? > drivers/media/usb/uvc/uvc_ This line looks odd, because: > drivers/media/usb/uvc/uvc_driver.c | 2 +- > drivers/media/usb/uvc/uvc_video.c | 13 +++++++++---- > drivers/media/usb/uvc/uvcvideo.h | 4 ++-- > 3 files changed, 12 insertions(+), 7 deletions(-) Only 3 files were changed. What went wrong? thanks, greg k-h