On Mon, Dec 7, 2009 at 10:44 AM, Tomi Valkeinen <tomi.valkeinen@xxxxxxxxx> wrote: > Hi, > > On Fri, 2009-12-04 at 11:53 +0100, ext Grazvydas Ignotas wrote: >> hi, >> >> it seems DSS block in OMAP needs SDI/DSI supplies to operate properly >> even with parallel displays, or else it doesn't drive some data lines >> resulting in missing/wrong colors. Take a look at figure 15-1 on OMAP3 >> TRM (page 2119 on spruf98d), some dss_data lines are going out of >> SDI/DSI blocks, which are fed by vdds_sdi and vdds_dsi supplies >> (vdss_sdi in fig 15-1 seems to be a typo). Those 2 are typically >> connected to VPLL2 on TWL4030/TPS65950 (see fig. 25-2 on p3482), so >> that regulator needs to be activated for proper operation (if you have >> a parallel display and a board with TWL4030 you can reproduce this by >> not enabling VPLL2 in bootloader and kernel; mainline u-boot enables >> it). > > Hmm, this would explain the color errors. Have you seen this on some > other board than TI's SDP? > > To me the fig 15-1 does not tell that the powers are needed. The > DSS_DATA[] pins do not come from SDI/DSI blocks, but from the main DSS > block. And the pin muxing component is outside also. This of course > doesn't really prove anything. =) True, but apparently vdds_dsi and/or vdds_sdi are also used to drive some data lines then (not supplying them produces blue-ish display with some parts missing). I'm working with pandora board, and I'm sure VPLL2 is not connected to anything else. > >> Right now DSS2 requests vdds_dsi in DSI driver only, any plans to >> request vdds_dsi/vdds_sdi for parallel displays too? > > I didn't have any plans, but if what you said is true, it sure needs to > be added. Yeah that would be nice. > > Tomi > > Ps. Adding l-o, as others may be interested also. > > > -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
