4.9-stable review patch. If anyone has any objections, please let me know.
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From: Brad Love brad@nextdimension.cc
[ 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 brad@nextdimension.cc Reviewed-by: Michael Ira Krufky mkrufky@linuxtv.org Signed-off-by: Mauro Carvalho Chehab mchehab@s-opensource.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -189,7 +189,7 @@ 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