From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Brad Love , Michael Ira Krufky , Mauro Carvalho Chehab , Sasha Levin Subject: [PATCH 3.18 164/185] media: em28xx: USB bulk packet size fix Date: Mon, 28 May 2018 12:03:25 +0200 Message-Id: <20180528100112.284958395@linuxfoundation.org> In-Reply-To: <20180528100050.700971285@linuxfoundation.org> References: <20180528100050.700971285@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Brad Love [ Upstream commit c7c7e8d7803406daa21e96d00c357de8b77b6764 ] Hauppauge em28xx bulk devices exhibit continuity errors and corrupted packets, when run in VMWare virtual machines. Unknown if other manufacturers bulk models exhibit the same issue. KVM/Qemu is unaffected. According to documentation the maximum packet multiplier for em28xx in bulk transfer mode is 256 * 188 bytes. This changes the size of bulk transfers to maximum supported value and have a bonus beneficial alignment. Before: After: This sets up USB to expect just as many bytes as the em28xx is set to emit. Successful usage under load afterwards natively and in both VMWare and KVM/Qemu virtual machines. Signed-off-by: Brad Love Reviewed-by: Michael Ira Krufky Signed-off-by: Mauro Carvalho Chehab Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- drivers/media/usb/em28xx/em28xx.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/media/usb/em28xx/em28xx.h +++ b/drivers/media/usb/em28xx/em28xx.h @@ -183,7 +183,7 @@ USB 2.0 spec says bulk packet size is always 512 bytes */ #define EM28XX_BULK_PACKET_MULTIPLIER 384 -#define EM28XX_DVB_BULK_PACKET_MULTIPLIER 384 +#define EM28XX_DVB_BULK_PACKET_MULTIPLIER 94 #define EM28XX_INTERLACED_DEFAULT 1