ScreenModes_ReadInfo 1 (changes)
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ScreenModes
» SWI Calls
» ScreenModes_ReadInfo
» ScreenModes_ReadInfo 1
ScreenModes_ReadInfo 1
(SWI &487C0)
| Entry | |
|---|---|
| R0 | 1 |
| Exit | |
|---|---|
| R0 | |
| R1 | Validity mask |
| All other registers preserved | |
Use
This call provides a means for software to determine which speakers may be available on a given display. Normally this information is determined by reading the displaysDPMS state will be used when the screen is blanked. This will either be the DPMS state that was specified in the MDF, or the DPMS state that was extracted from the EDID.
Because the speaker mask is an optional part of the EDID, two values are returned: the speaker mask as reported from the monitor (in R0), and a validity mask (in R1) which indicates which bits of R0 have been specified. The following table can be used as a guide to determine whether a given speaker is available or not:
| Speaker mask bit value | Validity mask bit value | Interpretation |
|---|---|---|
| 0 | 0 | Monitor did not provide information – speaker may or may not be present |
| 0 | 1 | Speaker is not present |
| 1 | 0 | Reserved |
| 1 | 1 | Speaker is present |
Notes
Bit This allocation information in is of an informative nature; the two preferred words way follows for software to blank and unblank the same screen scheme is as via theCEAScreenBlanker 861 SWIs, speaker which allocation do data not block: require theDPMS state to be specified (the kernel, which is ultimately in charge of calling GraphicsV 4, will remember the DPMS state that was specified in the VIDC control list that was used during the last mode change).
| Bit | Interpretation |
|---|---|
| 0 | Front Left & Front Right |
| 1 | LFE |
| 2 | Front Center |
| 3 | Rear Left & Rear Right |
| 4 | Rear Center |
| 5 | Front Left Center & Front Right Center |
| 6 | Rear Left Center & Rear Right Center |
| 7+ | Reserved |
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