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authorBrad Love <brad@nextdimension.cc>2018-01-04 19:04:13 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-05-30 07:47:43 +0200
commit9215e5a5af24a0e979f30faea9cf229fc8bbc4f1 (patch)
treebc4db857bd0aee752805e045128dca305021d2a7
parentf8c61fea834591cdb887b8ca2b60f761d42982b7 (diff)
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 <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>
-rw-r--r--drivers/media/usb/em28xx/em28xx.h2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h
index a21a7463b557..0b4825ed6886 100644
--- 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