projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 06e23a17 GKH |
1 | From foo@baz Thu May 24 11:09:34 CEST 2018 |
| 2 | From: Brad Love <brad@nextdimension.cc> | |
| 3 | Date: Thu, 4 Jan 2018 19:04:13 -0500 | |
| 4 | Subject: media: em28xx: USB bulk packet size fix | |
| 5 | ||
| 6 | From: Brad Love <brad@nextdimension.cc> | |
| 7 | ||
| 8 | [ Upstream commit c7c7e8d7803406daa21e96d00c357de8b77b6764 ] | |
| 9 | ||
| 10 | Hauppauge em28xx bulk devices exhibit continuity errors and corrupted | |
| 11 | packets, when run in VMWare virtual machines. Unknown if other | |
| 12 | manufacturers bulk models exhibit the same issue. KVM/Qemu is unaffected. | |
| 13 | ||
| 14 | According to documentation the maximum packet multiplier for em28xx in bulk | |
| 15 | transfer mode is 256 * 188 bytes. This changes the size of bulk transfers | |
| 16 | to maximum supported value and have a bonus beneficial alignment. | |
| 17 | ||
| 18 | Before: | |
| 19 | ||
| 20 | After: | |
| 21 | ||
| 22 | This sets up USB to expect just as many bytes as the em28xx is set to emit. | |
| 23 | ||
| 24 | Successful usage under load afterwards natively and in both VMWare | |
| 25 | and KVM/Qemu virtual machines. | |
| 26 | ||
| 27 | Signed-off-by: Brad Love <brad@nextdimension.cc> | |
| 28 | Reviewed-by: Michael Ira Krufky <mkrufky@linuxtv.org> | |
| 29 | Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com> | |
| 30 | Signed-off-by: Sasha Levin <alexander.levin@microsoft.com> | |
| 31 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 32 | --- | |
| 33 | drivers/media/usb/em28xx/em28xx.h | 2 +- | |
| 34 | 1 file changed, 1 insertion(+), 1 deletion(-) | |
| 35 | ||
| 36 | --- a/drivers/media/usb/em28xx/em28xx.h | |
| 37 | +++ b/drivers/media/usb/em28xx/em28xx.h | |
| 38 | @@ -191,7 +191,7 @@ | |
| 39 | USB 2.0 spec says bulk packet size is always 512 bytes | |
| 40 | */ | |
| 41 | #define EM28XX_BULK_PACKET_MULTIPLIER 384 | |
| 42 | -#define EM28XX_DVB_BULK_PACKET_MULTIPLIER 384 | |
| 43 | +#define EM28XX_DVB_BULK_PACKET_MULTIPLIER 94 | |
| 44 | ||
| 45 | #define EM28XX_INTERLACED_DEFAULT 1 | |
| 46 |