From e4504b80e012f6ca569a738b2dc3b70ae4f4ceb3 Mon Sep 17 00:00:00 2001 From: Brad Love Date: Thu, 4 Jan 2018 19:04:13 -0500 Subject: media: em28xx: USB bulk packet size fix [ 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(-) (limited to 'drivers/media') diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h index 88084f24f033..094e83b6908d 100644 --- a/drivers/media/usb/em28xx/em28xx.h +++ b/drivers/media/usb/em28xx/em28xx.h @@ -191,7 +191,7 @@ 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 -- cgit v1.2.3