Date: Wed, 10 Jun 2020 21:38:35 +0000 (UTC) From: Oleksandr Tymoshenko <gonzo@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r362029 - head/sys/dev/hdmi Message-ID: <202006102138.05ALcZZV087863@repo.freebsd.org>
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Author: gonzo Date: Wed Jun 10 21:38:35 2020 New Revision: 362029 URL: https://svnweb.freebsd.org/changeset/base/362029 Log: Fix reading EDID on TVs/monitors without E-DCC support Writing segment id to I2C device 0x30 only required if the segment is non-zero. On the devices without E-DCC support writing to that address fails and whole transaction then fails too. To avoid this do not attempt write to the segment selection device unless required. MFC after: 2 weeks Modified: head/sys/dev/hdmi/dwc_hdmi.c Modified: head/sys/dev/hdmi/dwc_hdmi.c ============================================================================== --- head/sys/dev/hdmi/dwc_hdmi.c Wed Jun 10 21:18:19 2020 (r362028) +++ head/sys/dev/hdmi/dwc_hdmi.c Wed Jun 10 21:38:35 2020 (r362029) @@ -658,6 +658,11 @@ hdmi_edid_read(struct dwc_hdmi_softc *sc, int block, u int result; uint8_t addr = block & 1 ? EDID_LENGTH : 0; uint8_t segment = block >> 1; + /* + * Some devices do not support E-DDC so attempt + * writing segment address only if it's neccessary + */ + unsigned char xfers = segment ? 3 : 2; struct iic_msg msg[] = { { I2C_DDC_SEGADDR, IIC_M_WR, 1, &segment }, { I2C_DDC_ADDR, IIC_M_WR, 1, &addr }, @@ -687,7 +692,7 @@ hdmi_edid_read(struct dwc_hdmi_softc *sc, int block, u return (result); } - result = iicbus_transfer(i2c_dev, msg, 3); + result = iicbus_transfer(i2c_dev, &msg[3 - xfers], xfers); iicbus_release_bus(i2c_dev, sc->sc_dev); if (result) {
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