GDS flow: Using pin thickness multipliers

[mtetrault]

I'm trying to change the pin thickness sizes (h_width/v_width) for the tiles using IO_PIN_V_THICKNESS_MULT/IO_PIN_H_THICKNESS_MULT parameters. While the default setting works with sg13g2, it led to occasional minor DRC errors with the openroad router in the PDK I'm using.

I tried putting the variables in the include/gds_config.yaml, [Tilename]/gds_config.yaml, and just in case in the Fabric/gds_config.yaml, but this doesn't seem to propagate to the run_***/resolved.json file. In effect, I'm always seeing the default value assigned (2).

Is this where the variables should be defined? If yes, any idea why it doesn't propagate to the json file?

For debug, I directly hardcoded a different multiplier value in the "tile_io_place.py". This did work to change the pin size, and the DRC errors were no longer in the layout.

[KelvinChung2000]

FABulous/fabulous/fabric_generator/gds_generator/steps/tile_IO_placement.py

Lines 81 to 84 in 39adb35

	"--hor-width-mult",
	str(self.config["IO_PIN_V_THICKNESS_MULT"]),
	"--ver-width-mult",
	str(self.config["IO_PIN_H_THICKNESS_MULT"]),

Because they are flipped by accident. Thanks for the report.

[KelvinChung2000]

But they should just propagate when you set them in the <tile-name>/gds_config.yaml. I will have a look at why.

Librelane is filtering the variable propagation again... I will push a fix once I figure out what need to be done.

[KelvinChung2000]

The issue is that we have not fully updated the default library values. So if you check your include/gds_config.yml, it has the FP_IO_HTHICKNESS_MULT, and that key is overriding the IO_PIN_H_THICKNESS_MULT in the <tile-name>/gds_config.yaml. Once you update the incldue/gds_config.yml from FP_IO_HTHICKNESS_MULT to IO_PIN_H_THICKNESS_MULT, the setting should propagate correctly.

The include/gds_config.yml acts as the base config file, and anything in the tile config will override it. But since the base is not getting the correct name, the overriding is not done correctly. When both of the variables are presented, Librelane is taking in the config, which somehow takes the deprecated entry with higher priority and overwrites.

[mtetrault]

Ah, there it was; using that key it works normally. Thanks!