Bug 16651

Summary:	Output of drm_cvt_mode function incorrect for reduced blanking modes
Product:	Drivers	Reporter:	Adam Serbinski (adam)
Component:	Video(DRI - non Intel)	Assignee:	drivers_video-dri
Status:	RESOLVED CODE_FIX
Severity:	normal	CC:	ajax
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:	2.6.35	Subsystem:
Regression:	No	Bisected commit-id:

Description Adam Serbinski 2010-08-21 02:36:51 UTC

drivers/gpu/drm/drm_modes.c
function drm_cvt_mode

When parameter "reduced" is set to TRUE, the hsync_start and hsync_end values calculated are... wrong, and the vsync_start and vsync_end values aren't calculated at all.

Output from command "cvt -r 1920 1200":
# 1920x1200 59.95 Hz (CVT 2.30MA-R) hsync: 74.04 kHz; pclk: 154.00 MHz
Modeline "1920x1200R" 154.00 1920 1968 2000 2080 1200 1203 1209 1235 +hsync -vsync

The values generated by drm_cvt_mode(dev,1920,1200,60,true,false,false) are:
154.00 1920 32 32 2080 1200 0 0 1235 +hsync -vsync

Comment 1 Adam Jackson 2010-08-23 14:32:25 UTC

Try this patch:

http://lists.freedesktop.org/archives/dri-devel/2010-August/003223.html

Comment 2 Adam Serbinski 2010-08-24 12:25:43 UTC

That did the job.

Thank you.