4. Module Loading

4.1. Principle

a certainsome Linux Framebuffer driver (if versa) not supportedinrunduringchangeresolution, color depth, timingetc.displayattribute. forthis, Linux systemprovidea type ofmechanism, allowininkernelbootorModule Loadingwhen, throughparameterwillcorrespondingoptionpassgive Linux Framebuffer. throughthistypemechanism, usercaninsystembootbefore, presetfirstconfiguredisplayrelatedparameter, withmeet specificapplicationrequirement. canininkernelloaderinconfigureinkernelbootparameter, for examplespecifiedresolution, refreshrateorcolor depthetc.. need toNoteis, GFBG driverinloadwhenonlycansetphysical video memorysize, notallowsetitsitoption. therefore, inuse GFBG driverwhen, userneed toaccording toactualrequirementraisebeforeplanningvideo memorysize, andinModule Loadingwhencorrectpassparameter. thismeansuserneed toinsystemdesignstepsegmentfully considerapplicationscenerequirement, for exampleiswhetherneed tosupporthighresolutiondisplayormultiplelayeroverlayaddgraphicalrendering. throughreasonableplanningvideo memorysize, canensuresysteminrunwhencanmeetperformanceandfunctionneed torequest, at the same timeavoidbecause ofvideo memorynotsufficientcausedisplayabnormalityorperformanceunderreduce.

4.2. Parameter Settings

GFBG can configureitsmanage overlaygraphicallayerphysical video memorysize. physical video memorysizedetermine GFBG can usemaximumphysical video memoryandsystemcan setvirtualresolution. inload GFBG driverwhenthroughparameterpasssetphysical video memorysize, physical video memorysizeonealreadysetthennotwillchangechange. thismeansuserinconfigurevideo memorysizewhenneed tofully considerapplicationactualrequirement, for exampleiswhetherneed tosupporthighresolutiondisplaycontentorresetcomplexgraphicaloverlayaddeffect. video memorysizesetdirectlyconnecteffecttosystemdisplaycapabilityandperformance, thereforerecommenduserinconfigurewhenaccording tospecificapplicationsceneperform testandverification. thisoutside, reasonablevideo memoryplanningnotonlycanimprovesystemstability, alsocanavoidresourcewaste, fromandoptimizesystementirebodyperformance.

4.2.1. Parametersvideo

video="gfbg:vram0_size:xxx, vram1_size:xxx, ..."

  • gfbg: meansload GFBG driver.

  • vram0_size: means GFBG managegraphicallayer0physical video memorysize, CV184X onlyhasgraphicallayer0, only supports vram0_size.

  • vram1_size: means GFBG managegraphicallayer1physical video memorysize.

  • xxx: meansphysical video memorysize, unitis KB.

  • If layernotconfigurephysical video memorysize, currentbeforedriverdefaultallocateis8100KB.

4.2.2. Relationship Between Physical Video Memory and Virtual Memory

For GFBGstandardmode, vramn_size andvirtualresolutionrelationshipas follows: vramn_size * 1024 >= xres_virtual * yres_virtual * bpp; wherexres_virtual * yres_virtual isvirtualresolution, bpp iseachpixeltheoccupybytesnumber.

4.2.3. Default Parameter Values

CV184X GFBG driverdefaultparameteris: video="gfbg:vram0_size:8100", that is, 1080presolution, 32bitscolor depthneed tominimumvideo memory. userneed tofromglobal perspectiveoutsendconfigure GFBG need tomanage overlaygraphicallayer, andiseachoverlayaddgraphicallayerallocateappropriatevideo memory.