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Commit 42fb1427 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Dave Airlie
Browse files

drm/ast: Don't assume DVO enabled means SIL164 on uninitialized chips 



It looks like the AST2400 comes up with the DVO enable bit set,
which causes us to incorrectly assume we have a SIL164 regardless
of the value of the scratch registers setup by the BMC firmware.

So let's limit that test to the case where the chip has already
been setup by a BIOS.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
parent 261a3ad4

drivers/gpu/drm/ast/ast_main.c

+10 −4
Original line number Diff line number Diff line
@@ -158,16 +158,22 @@ static int ast_detect_chip(struct drm_device *dev, bool *need_post) 
	/*

	 * VGACRA3 Enhanced Color Mode Register, check if DVO is already

	 * enabled, in that case, assume we have a SIL164 TMDS transmitter

	 *

	 * Don't make that assumption if we the chip wasn't enabled and

	 * is at power-on reset, otherwise we'll incorrectly "detect" a

	 * SIL164 when there is none.

	 */

	if (!*need_post) {

		jreg = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xa3, 0xff);

		if (jreg & 0x80)

			ast->tx_chip_type = AST_TX_SIL164;

	}



	if ((ast->chip == AST2300) || (ast->chip == AST2400)) {

		/*

		 * On AST2300 and 2400, look the configuration set by the SoC in

		 * the SOC scratch register #1 bits 11:8 (interestingly marked

		 * as "reserved" in the spec

		 * as "reserved" in the spec)

		 */

		jreg = ast_get_index_reg_mask(ast, AST_IO_CRTC_PORT, 0xd1, 0xff);

		switch (jreg) {