On Wed, Nov 20, 2024 at 05:37:35PM +0100, Caleb Connolly wrote: > > > On 20/11/2024 17:03, Simon Glass wrote: > > Hi Caleb, > > > > On Wed, 20 Nov 2024 at 08:56, Caleb Connolly <caleb.conno...@linaro.org> > > wrote: > >> > >> Hi Simon, > >> > >> On 20/11/2024 16:35, Simon Glass wrote: > >>> This series provides a way to tell a serial UART that it can't actually > >>> work, at runtime. The main motivation is to deal with a coreboot feature > >>> where it does not provide UART details in the sysinfo structure unless > >>> the UART is also enabled in coreboot. > >> > >> Why is the UART driver probed if coreboot doesn't provide the necessary > >> info for it? > > > > U-Boot doesn't do well without some sort of serial device. That could > > perhaps be improved. But the point here is that we need a single > > U-Boot build which can start from coreboot, regardless of what > > coreboot decides to do. > > Right, I'm suggesting that at runtime you notice that coreboot didn't > provide a serial port definition (or gave you a bogus address or > something) and skip probing the serial port in that case. > > > >> > >> Couldn't you disable CONFIG_REQUIRE_SERIAL_CONSOLE and skip probing it? > > > > No, because I want it to work if the serial info is available. > > This option doesn't disable the serial port, it just makes U-Boot not > panic if it can't find one. For example I enable this when building > U-Boot for the upstream supported Qualcomm phones since many don't > enable the serial port in their DTS.
Yes, this feels like an oddly coreboot specific solution to a generic problem that we should be able to handle already I thought? Like a Pi can have or not have a serial port enabled and still have video and we use that. We might well need something specific to know the port is disabled since I gather we aren't getting a devicetree that says status = disabled in it. But this ought to be a common enough general case? -- Tom
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