- int vga_switcheroo_lock_ddc(struct pci_dev * pdev);
- client pci device
Temporarily switch DDC lines to the client identified by pdev (but leave the outputs otherwise switched to where they are). This allows the inactive client to probe EDID. The DDC lines must afterwards be switched back by calling vga_switcheroo_unlock_ddc, even if this function returns an error.
Previous DDC owner on success or a negative int on error. Specifically, -ENODEV if no handler has registered or if the handler does not support switching the DDC lines. Also, a negative value returned by the handler is propagated back to the caller. The return value has merely an informational purpose for any caller which might be interested in it. It is acceptable to ignore the return value and simply rely on the result of the subsequent EDID probe, which will be NULL if DDC switching failed.
Jesse Barnes <[email protected]>
- Initial version
Laurent Pinchart <[email protected]>
Ideas on board SPRL,
- Driver internals
Daniel Vetter <[email protected]>
- Contributions all over the place
Lukas Wunner <[email protected]>
- vga_switcheroo documentation